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{{about|the domestic dog}}
{{subpages}}
{{Taxobox
{{Taxobox
| color = pink
| color = pink
| name = Domestic dog
| name = Domestic dog  
| status = {{StatusDomesticated}}
| status =  
| image = YellowLabradorLooking.jpg
| image =  
| image_width = 240px
| image_width =  
| image_caption = '''[[Labrador Retriever]]'''<br>a breed of domestic dog
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| domain = [[Eukaryota]]
| domain = [[Eukaryota]]
| regnum = [[Animal]]ia
| regnum = [[Animal]]ia
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| species = ''[[Grey Wolf|C. lupus]]''
| species = ''[[Grey Wolf|C. lupus]]''
| subspecies = '''''C. l. familiaris'''''
| subspecies = '''''C. l. familiaris'''''
| trinomial = ''Canis lupus familiaris''
| trinomial = ''Canis lupus familiaris''<ref>[[International Commission of Zoological Nomenclature]]: [http://www.iczn.org/BZNMar2003opinions.htm#opinion2027 Opinion 2027: Usage of 17 specific names based on wild species which are pre-dated by or contemporary with those based on domestic animals (Lepidoptera, Osteichthyes, Mammalia): conserved]</ref>
}}
}}
'''Dogs''' are [[artificial selection|domesticated]] [[canines]] that have been closely associated with humans ever since they first evolved from [[Canis lupus|gray wolves]] several thousand years ago. Throughout the world dogs are still intimately associated with humans in a variety of roles, and because of this they are often called "man's best friend". Today they are nearly ubiquitous, as household [[pet]]s, cherished companions, full-time workers, and even, in some cultures, as food.


The '''dog''' is one of the first of the animals domesticated. Throughout most of the world, dogs can be found associated with humans, their status in society ranging from a form of food to a cherished companion.   
Dogs and people may communicate better with each other than any other two [[species]].<ref>Stephen Budiansky, The Truth about Dogs: An Inquiry into Ancestry Social Conventions. Mental Habits Moral Fiber ''Canis familiaris''. 2001 ISBN 014100228X</ref> Dogs and humans understand each other on a basic level: we are able to interpret the dog's instinctive body language (along with canine vocalizations like the growl and whine); and the dog, in turn, has an innate ability to respond appropriately both to human body language, as well as to the emotional tone of the human voice.  Some research suggests that dogs may be better at interpreting cues from humans than even our closest relatives, the [[chimpanzee]]s. <ref>  In an 2002 article for BBC News Online, Christine McGourty cites two separate American studies, one at Harvard University and the other at the Wolf Hollow Wolf Sanctuary, both in the United States. Puppies were found to be as good as older dogs at finding hidden food using clues from humans. [http://news.bbc.co.uk/h/hi/science/nature/2498669.stm] sourced on 7/20/2007. </ref>People can be educated beyond these basics to manage their dogs more precisely, and dogs can be trained to be extremely responsive to people. In addition, dogs can modify the behaviour of their humans to a surprising degree.
   
==The origin of the dog==


===Ancestry===
By the mid-20th Century, scientists had generally agreed that the immediate ancestor of the dog must be one of its close living relatives: [[jackal]]s, [[coyote]]s or [[wolf|wolves]], but they had trouble deciding on which one.<ref> Ashworth,  Lou Sawyer and Kraft, Irene. ''The Concise Encyclopedia of Dogs.''  London: Octopus Books, 1974. pgs. 79-81.</ref> Most early research depended on [[archeology|archeological]] evidence to try to solve the riddle of the dog's origin.


This issue was finally solved using [[DNA]] which proved that the [[Canis lupus|Gray Wolf]] is the sole ancestor of all modern dogs.<ref name=Savolainen>Savolainen, P., Y. P. Zhang, J. Luo, J. Lundeberg, and T. Leitner.  2002.  Genetic evidence for an East Asian origin of domestic dogs.  Science 298:1610-1613.</ref><ref name=Vila>Vila, C., P. Savolainen, J. E. Maldonado, I. R. Amorim, J. E. Rice, R. L. Honeycutt, K. A. Crandall, J. Lundeberg, and R. K. Wayne.  1997.  Multiple and ancient origins of the domestic dog.  Science 276:1687-1689.</ref> Therefore, dogs are a subspecies (''Canis lupus familiaris'') of the Gray Wolf (''Canis lupus'').<ref>Don E. Wilson & DeeAnn M. Reeder (editors). 2005. Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed), Johns Hopkins University Press, 2,142 pp. </ref> The most likely ancestors are [[Asian]] populations of the wolves, based on the diversity of comparing the genetic diversity of Asian wolves with that of modern dog breeds <ref name=Savolainen/> while the data is consistent with multiple domestication events. <ref name=Savolainen/><ref name=Vila/>


Dogs are like humans in being highly [[social animal]]s. The loyalty and devotion that dogs demonstrate as part of their natural instincts as pack animals closely mimics the human idea of love and friendship, leading many dog owners to view their pets as full-fledged family members. Conversely, dogs seem to view their human companions as members of their pack, and make few, if any, distinctions between their owners and fellow dogs. Dogs fill a variety of roles in [[human society]] and are often trained as [[working dog]]s. For dogs that do not have traditional jobs, a wide range of [[dog sports]] provide the opportunity to exhibit their natural skills. In many countries, the most common and perhaps most important role of dogs is as [[companion dog|companions]]. Dogs have lived with and worked with humans in so many roles that their loyalty has earned them the unique [[sobriquet]] "man's best friend" <ref> http://www.almostheaven-golden-retriever-rescue.org/old-drum.html </ref> Conversely, some cultures consider dogs to be [[unclean animals|unclean]]. In some cultures, certain types of dogs are used as [[taboo food and drink|food]].
===The domestication of the dog===
Through the 1970s and 1980s, schoolchildren were taught that humans domesticated the dog. Nowadays,  many scientists feel that a more accurate description would be that the relationship evolved on a more equal footing, with humans and dogs coming together to ensure their mutual survival in a hostile environment.  Another way of looking at the question would be to ask if the domestication of the dog was a result of [[natural selection]], in which nature plays the larger part in deciding which dogs survive; in this case the dogs which adapted most readily to humans in their environment, or of [[artificial selection]]--humans picking which dogs contributed to the gene pool based on which had traits humans found desirable--the precursor of selective breeding. Surveys and analysis have made cases for both theories.  <ref>  The idea of the wolf being more proactive in its "domestication" became more seriously discussed in 1he 1990s.  ''From Wolf to Dog'' New York Times, September 24, 2007, discusses competing theories.  Ray and Lorna Coppinger argue in ''Dogs: A New Understanding of Canine Origin, Behavior and Evolution,'' that this was natural selection, in which scavenger wolves hung about human encampments; the ones who became less afraid of people got the first pick of human waste (food), and therefore thrived.  ''Wolf to Woof:  The Evolution of dogs'', National Geographic, January 2002, and Dr Bruce Fogle in ''The New Encyclopedia of the Dog'' discuss the same idea. However, the idea that primitive humans ''selected'' the tamest wolf cubs and bred like to like over successive generation still has its adherents.  ''Dogs and more dogs, an Affectionate Analysis.''  Video recording. ''Nova'', WGBH, Boston, 2004. </ref>


==Terminology==  
===The history of the relationship between humans and dogs===
"Dog" is sometimes used to refer collectively to any mammal belonging to the family ''[[Canidae]]'' (as in "the dog family"), such as wolves, foxes, and coyotes. Some members of the family have "dog" in their common names, such as the [[African Wild Dog]]. The constellations [[Canes Venatici]], [[Canis Major]] and [[Canis Minor]] are named from the [[Latin language|Latin]] word for "dog," for their perceived resemblance to dogs.
The relationship between humans and dogs is certainly an ancient one.  Cave paintings such as one found in Tassili n'Ajjer suggest that primitive man and dog were already living in harmony. <ref> The site is referred to as Tessili-n-Ajjer in ''The Concise Encyclopedia of Dogs'' op.cit.</ref>  Dogs in such images are portrayed as hunters, both in the company of humans and alone, which can be taken as an indication of a developed relationship.  Precise dates for these drawings are frequently debated, as they existed before recorded history, and our dating techniques can be affected by many factors, but some of this [[rock art]] is several thousand years old. The earliest known domestic dog remains  "may date back as far as 10,000 BC, preceding the Neolithic period....evidence indicates that dogs were kept in Jericho by 6500 BC." <ref>Alderton, David.  ''The Dog: The Complete Guide to Dogs and Their World.  London: New Burlington Books, 1987. </ref>


The English word ''dog'' derives from the Old English [[wikt:docga|docga]], a "powerful breed of canine". The French ''dogue'' and Spanish ''dogo'' as in [[dogo Argentino]] are borrowings from English. The English word ''hound'' is a cognate of the German ''Hund'' and Dutch ''hond'', which applies to all breeds. ''Hound'' itself, like Latin [[canis]] and Greek κυων (kuōn), derive ultimately from the [[Proto-Indo-European]] *kuon-.
By the time of the pharaohs, dogs had already established their value as workers and human companions.  Egyptian paintings show that [[selective breeding]] had already begun; [[sighthound]]s were clearly identified.  Dog mummies have been found in the tombs of Pharaohs. The Assyrians, Greeks and Romans all used dogs for hunting and as battle companions.  [[Pliny the Elder]] described the value of dogs in no uncertain terms, and also referred to the existence of--if not refined dog breeds, certainly defined dog types.<ref> ''The Concise Encyclopedia of Dogs'' contains illustrations of domestic dogs from a Minoan painting, circa 2000 B.C. and an Egyptian painting circa 1450 B.C., both depicting hounds, and an Assyrian relief depicting a mastiff type hunting dog in what appears to be a choke collar. </ref> <ref>  See for example the bas-relief of Asshurbanipal, c. 2000 B.C. This and a Greek vase showing a depiction of a mythological tale featuring dogs are illustrated in ''The Dog'' by Alderton, op. cit.</ref> <ref> Pliny the Elder, ''Natural History'' </ref> A Chinese ceramic statue from the era of the T'ang Dynasty, circa 700 A.D., depicts a dog bearing a resemblance to today's [[Dandie Dinmont Terrier]]. <ref> ''The Concise Encyclopedia of Dogs'', op. cit.</ref>


In breeding and show circles, a male canine is referred to as a ''dog'', while a female canine is called a ''bitch''. Offspring are generally called ''pups'' or ''[[puppy|puppies]]'' until they are about a year old. A group of offspring is a ''litter''. The process of birth is ''whelping''. Many [[Mixed-breed dog#Terms for mixed-breed dogs|terms are used for dogs]] that are not purebred.
By the medieval period, hunters had classified dogs according to the type of game they were best suited to handle.<ref> Dame Juliana Berners  ''The Boke of St Albans'' 1496, a hunting reference book. </ref>.  By the 16th Century, ''Of Englische Dogges'', the first written work specifically and exclusively about dogs, appeared. <ref> Dr John Caius, ''Of Englische Dogges'': Dr Johannes Caius, ''De Canibus Brittanicus'' (1570) and translated by Abraham Fleming as ''Of Englishe Dogges'' (1576).</ref> Illustrations in ''The Hunt of the Unicorn'', a series of medieval tapestries attributed as Flemish, circa 1500, show many domesticated hunting dogs, including hounds and terriers, and one somewhat like a Great Dane. <ref> The tapestries are now in [[The Cloisters]] museum in New York City.  This is also illustrated in Alderton, op. cit. </ref>


==Intelligence==
==Dog anatomy and health==
{{main|Dog intelligence}}
Modern [[dog breed]]s show more variation in size, appearance, and behavior than any other domestic animal.
Among dog lovers, dogs are generally valued for their intelligence, and both [[anecdotal evidence]] and [[Scientific method|scientific research]] suggest that dogs have a reasonably high intelligence. This intelligence is expressed differently with different breeds and individuals, however. For example, [[Border Collie]]s are noted for their ability to learn commands, while other breeds may not be so motivated towards obedience, but instead show their cleverness in devising ways to steal food or escape from a yard. Dogs are descended from wolves, and are also pack animals, making them easier than other animals to train because dogs' instincts are to obey. But most dogs rarely have to deal with complex tasks and are unlikely to learn relatively complicated activities (such as opening doors) unaided. Some dogs (such as guide dogs for the visually impared) are specially trained to recognize and avoid dangerous situations.


==Physical characteristics==
[[Image:Dog-closeup.jpg|thumb|right|150px|Even a friendly dog has sharp teeth.]]
{{main|Dog anatomy}}
===Physical characteristics===
[[Image:DSC01405.JPG|thumb|left|[[Shiba Inu]]s have a unique appearance that resembles foxes.]]
Dogs generally share attributes with their wild ancestors, the [[Gray Wolf|wolves]]. Dogs are both [[predator]]s and [[scavenger]]s, possessing sharp [[tooth|teeth]] and strong [[jaw]]s for attacking, holding, and tearing their food. Although [[selective breeding]] has changed the appearance of many [[dog breed|breed]]s, all dogs retain basic traits from their distant ancestors. Like many other predatory mammals, the dog has powerful [[muscle]]s, fused wrist [[bone]]s, a [[cardiovascular]] system that supports both sprinting and endurance, and teeth for catching and tearing. Compared to the bone structure of the human [[foot]], dogs technically walk on their toes.
[[Image:Weimaraner wb.jpg|thumb|right|Some dogs, like this [[Weimaraner]], have their predatory instincts suppressed in order to better assist human hunters.]]
[[Image:Amazonian Dog.JPG|right|A|thumb|200px|Amazonian dogs, such as this one from [[Alto Amazonas]], [[Peru]] are critical for [[indigenous peoples]]' [[hunting]] strategies, particularly in the [[rain forest]].]]
[[Image:Cattledogwithbone.JPG|thumb|This [[Australian Cattle Dog]] puppy, bred to herd livestock in the heat and harsh conditions of the bush, enjoys a bone.]]
{{see also|Dog health}}
Modern [[dog breed]]s show more variation in size, appearance, and behavior than any other domestic animal. Within the range of extremes, dogs generally share attributes with their wild ancestors, the [[Gray Wolf|wolves]]. Dogs are [[predator]]s and [[scavenger]]s, possessing sharp teeth and strong jaws for attacking, holding, and tearing their food. Although selective breeding has changed the appearance of many breeds, all dogs retain basic traits from their distant ancestors. Like many other predatory mammals, the dog has powerful muscles, fused wristbones, a [[cardiovascular]] system that supports both sprinting and endurance, and teeth for catching and tearing. Compared to the bone structure of the human foot, dogs technically walk on their toes.


===Sight===
===Sight===
Dogs were thought to be [[dichromat]]s and thus, by human standards, [[color blind]].<ref name="note1">A&E Television Networks (1998). ''Big Dogs, Little Dogs: The companion volume to the A&E special presentation'', A Lookout Book, GT Publishing. ISBN 1-57719-353-9 (hardcover).</ref><ref name="note2">Alderton, David (1984). ''The Dog'', Chartwell Books. ISBN 0-89009-786-0.</ref> New research is now being explored that suggests that dogs may actually see some color, but not to the extent that humans do; color may serve as a subliminal signal helping to distinguish overlapping objects from each other, rather than a distinct feature that the dog can directly determine. It has also been suggested that dogs see in varieties of purple/violet and yellow shades. Because the lenses of dogs' eyes are flatter than humans', they cannot see as much detail; on the other hand, their eyes are more sensitive to light and motion than humans' eyes. Some breeds, particularly the best [[sighthound]]s, have a field of vision up to 270° (compared to 180° for humans), although broad-headed breeds with their eyes set forward have a much narrower field of vision, as low as 180°.<ref name="note1" /><ref name="note2" />
Because the lenses of dogs' [[eye]]s are flatter than humans', they cannot see as much detail; on the other hand, their eyes are more sensitive to light and motion than humans' eyes. Some dogs, the sight hounds, have been specifically bred to capitalize on their use of [[vision]] in tracking prey. These breeds include the [[Greyhound]] and [[Afghan Hound]].<ref>{{cite web | last = | first = | authorlink = | coauthors = Jonica Newby, Caroline Penry-Davey | title = Catalyst: Dogs' Eyes | work = | publisher = Australian Broadcasting Corporation | date = 2003-09-25 | url = http://www.abc.net.au/catalyst/stories/s953902.htm | format = | doi = | accessdate = 1st April 2007 }}</ref> The most capable [[sighthound]]s have a field of vision up to 270° (compared to 180° for humans). Broad-headed dog breeds with forward set eyes have a much narrower field of vision, sometimes no wider than the human 180 degrees.


===Hearing===
===Hearing===
[[Image:PennyAlertPricksEars.jpg|thumb|left|This [[Collie]]/[[Saluki]] angles her ears to find the source of a sound.]]
Dogs detect sounds as low as the 16 to 20 [[Hertz|Hz]] frequency range (compared to 20 to 70 Hz for humans) and as high as 70 kHz to 100 kHz (compared to 13 to 20 kHz for humans), and in addition have a degree of ear mobility that helps them to rapidly pinpoint the exact location of a sound. Eighteen or more muscles can tilt, rotate and raise or lower a dog's ear. The dog's sensitivity to even very quiet sounds, as compared to a human’s, means that a dog can identify a sound's location much faster, as well as hear sounds that are coming from far more distant sources than a human companion by its side.<ref>[http://www.lsu.edu/deafness/HearingRange.html How well do dogs hear?] Accessed 1st April 2007</ref>
Dogs detect sounds as low as the 16 to 20[[Hertz|Hz]] frequency range (compared to 20 to 70 Hz for humans) and as high as 70 kHz to 100 kHz (compared to 13 to 20 kHz for humans)<ref name="note2" />, and in addition have a degree of ear mobility that helps them to rapidly pinpoint the exact location of a sound. Eighteen or more muscles can tilt, rotate and raise or lower a dog's ear. Additionally, a dog can identify a sound's location much faster than a human can, as well as hear sounds up to four times the distance that humans are able to. Those with more natural ear shapes, like those of wild canids like the fox, generally hear better than those with the floppier ears of many domesticated species.
 
Those with more open ear shapes, like the erect ears of wild [[canid]]s like the [[fox]], generally hear better than those with the floppier ears of many domesticated species.


===Smell===
===Smell===


Dogs have nearly 220 million smell-sensitive cells over an area about the size of a pocket [[handkerchief]] (compared to 5 million over an area the size of a [[postage stamp]] for humans). Some breeds have been selectively bred for excellence in detecting scents, even compared to their canine brethren. What information a dog actually detects when he is scenting is not perfectly understood; although once a matter of debate, it now seems to be well established that dogs can distinguish two different types of scents when trailing, an air scent from some person or thing that has recently passed by, as well as a ground scent that remains detectable for a much longer period. The characteristics and behavior of these two types of scent trail would seem, after some thought, to be quite different, the air scent being intermittent but perhaps less obscured by competing scents, whereas the ground scent would be relatively permanent with respect to careful and repetitive search by the dog, but would seem to be much more contaminated with other scents. In any event, it is established by those who train tracking dogs that it is impossible to teach the dog how to track any better than it does naturally; the object instead is to motivate it properly, and teach it to maintain focus on a single track and ignore any others that might otherwise seem of greater interest to an untrained dog. An intensive search for a scent, for instance searching a ship for contraband, can actually be very fatiguing for a dog, and the dog must be motivated to continue this hard work for a long period of time.
Dogs have nearly 220 million smell-sensitive cells over an area about the size of a pocket [[handkerchief]] (compared to 5 million over an area the size of a [[postage stamp]] for humans). It is fair to say that all dogs have a richer olfactory experience than ours. Some breeds have been selectively bred for excellence in detecting scents, over and above their canine brethren, such as the [[scent hound]]s, including and particularly [[Bloodhounds]].
 
==Reproduction==
===The dog's reproductive cycle===
:''See the main article at [[dog reproduction]].''
 
''Bitches'' (female dogs) have a reproductive cycle that generally varies from six months to one year, although there ''are'' bitches that come into [[oestrus]] more or less frequently. This ''season'' is the only time that bitches are receptive to mating.


==Diet==
Gestation, the period in which mammals carry their developing young in the uterus, lasts about two months (60-64 days). Whelping (the birth of puppies) usually takes place without incident.  The ''dam'' (mother) ordinarily gives birth to more than one puppy at a time.  The group of pups born together is known as a ''litter''.
 
Unlike human females, bitches remain fertile throughout their adult lives.
 
===Dog breeding===
:''See the main article at [[dog breeding]].''


At present, there is some debate as to whether domestic dogs should be classified as [[omnivores]] or [[carnivores]], by diet.
Dog breeders mate selected dogs together hoping to reproduce desired traits in the resulting offspring.  Those who breed working dogs, such as herders, pick breeding stock that have instincts and abilities suited to the tasks the dogs are required to perform. By contrast, people who breed show dogs have strict sets of criteria to conform to; these are largely related to the dog's appearance and personality.
The classification in the Order [[Carnivora]] does not necessarily mean that a dog's diet must be restricted to [[meat]]; unlike an obligate carnivore, such as the [[cat]] family with its shorter [[small intestine]], a dog is dependent on neither meat-specific protein nor a very high level of protein in order to fulfill its basic dietary requirements. Dogs are able to healthily digest a variety of foods including [[vegetable]]s and [[cereal|grains]], and in fact can consume a large proportion of these in their diet. Wild canines not only eat available plants to obtain [[essential amino acid]]s, but also obtain nutrients from vegetable matter from the stomach and intestinal contents of their [[herbivorous]] prey, which they usually consume. Domestic dogs can survive healthily on a reasonable and carefully designed [[vegetarian]] diet, particularly if [[egg (food)|eggs]] and [[milk]] products are included. Some sources suggest that a dog fed on a [[strict vegetarian]] diet may develop [[dilated cardiomyopathy]] since it lacks [[L-carnitine]], <ref>''Small animal internal medicine'', RW Nelson, Couto page 107</ref> however, maintaining a balanced diet is also a factor since [[L-carnitine]] is found naturally in many [[nut (fruit)|nuts]], [[seed]]s, [[bean]]s, [[vegetable]]s, [[fruit]]s and [[whole grain]]s. In the wild, dogs can survive on a vegetarian diet when animal prey is not available. However it has been noted, both by observation of extremely stressful conditions such as the [[Iditarod]] race and by scientific studies of similar conditions, that high-protein (approximately 40%) diets including meat help prevent damage to [[muscle]] tissue. (This research is also true for some other mammals.) This level of protein corresponds to the percentage of protein found in the wild dog's diet when prey is abundant; higher levels of protein seem to confer no added benefit.


Dogs frequently avidly eat [[grass]], a harmless activity. Explanations abound, but rationales such as that it neutralizes [[acid]], or that eating grass might make the dog [[vomit]], so dogs eat grass to remove unwanted substances from their [[stomach]]s, are at best educated guesses. Dogs do vomit more readily than humans, as part of their typical feeding behavior of gulping down food then regurgitating indigestible bones, fur, ''etc.'' This behavior is typical of pack feeding in the wild, where the most important thing is to get as much of the kill as possible before others consume it all. Individual domestic dogs, however, may be very "picky" eaters, in the absence of this evolutionary pressure.  
Formal dog organisations record purebred dogs in [[breed registry|breed registries]].


===Dangerous substances===
==Dogs and humans in daily life==
Some foods commonly enjoyed by humans are dangerous to dogs, including [[chocolate]] ([[Theobromine poisoning]]), [[onion]]s, [[grape]]s and [[raisin]]s <ref>{{cite web | url = http://www.aspca.org/site/News2?page=NewsArticle&id=16645 | title = ASPCA Animal Poison Control Center Issues Nationwide Update: Raisins and Grapes Can Be Toxic To Dogs | accessmonthday = September 2 | accessyear = 2006 | date = 2004-07-06 | work = ASPCA Press Releases | publisher = American Society for the Prevention of Cruelty to Animals }}</ref>, some types of [[chewing gum|gum]], and [[Macadamia nut]]s. Now that it is thought that the only dangerous substance in chocolate is the [[cocoa]], this means that [[white chocolate]] can be used as a rare treat.
Some dog owners view their pets as fully-fledged family members, and most dogs are able to act the part. That ability stems from two basic sources: (1) the "hard-wiring" of the dog's behavior (programmed by its canine genes), and (2) the individual dog's experience with people. Dogs are, like humans, highly [[social animal]]s. Although the instincts to behave in ways that ease interactions in the [[pack (canine)|pack]] are inborn in all normal dogs, the right early experiences are [[critical period|critical]] if puppies are to grow up into companionable dogs. Those "right" experiences have everything to do with contact with people and with other dogs, and they must occur early in the dog's life - probably before the puppy reaches 12 weeks of age.
[[Image:Sleeping Pups.jpg|right|thumb|250px|{{#ifexist:Template:Sleeping Pups.jpg/credit|{{Sleeping Pups.jpg/credit}}<br/>|}}Puppies are rarely born singly; the group of puppies born together is known as a ''litter''.]]


The acute danger from grapes and raisins has been uncovered only since about 2000, and made public slowly since then. At present the cause is not known, but one [[veterinarian]] <ref>{{cite web | url = http://dogtorj.tripod.com/id10.html | title = Who is DogtorJ? (Contact) | accessmonthday = September 2 | accessyear = 2006 | first = John B. | last = Symes}}</ref> believes it may be an acute [[auto-immune]] response to plant-borne viruses <ref>{{cite web | url = http://www.chazhound.com/forums/showthread.php?t=591 | title = Finally, some reliable info on grapes & raisins | accessmonthday = September 2 | accessyear = 2006 | author = Renee750il | work = Chazhound Dog Forum | date = 2004-07-17}}</ref> in the same manner as [[Feline infectious peritonitis|FIP]] in cats. Whatever the reason, since only small quantities are necessary to induce acute [[renal failure]], dogs should not be fed grapes or raisins, and perhaps [[Sultana (grape)|sultanas]] and [[currants]] should also be withheld.
When puppies are raised with plenty of close contact to people ''and'' to other dogs, they become fully [[Socialization|socialized]]. Socialized pups seem to view their human companions as members of their pack, and make few, if any, distinctions between their owners and fellow dogs. As these puppies mature, they can be taught to modify their behavior towards people, and treat their human companions more gently than their canine ones. Puppies who are raised without human nurturing have a harder time adjusting to interactions with owners once they have passed the critical period of about 3 months of age, no matter how much gentle attention is then given them. Orphaned puppies that are bottle fed and raised by humans alone, without any contact to any other dog or puppy, are in danger of becoming abnormally fixated on humans, and such puppies include animals that turn their attentions, sexual and social, to people instead of to dogs. [[Mounting behavior]], for example is an annoyance to visitors and an embarrassment for owners.  It not only signals sexual attention, but is a normal part of a dog's dominance behaviour, a tool for determining pack hierarchy.  Proper dog-human socialization establishes the human's position as pack leader early, and eliminates the need for such trials.


Cooked [[Bone|bones]] should '''never''' be given to dogs, as the heat changes the chemical and physical properties so that they cannot be chewed properly, splintering into jagged shards, and resist digestion.
The group of puppies born together is called a ''litter''. That means that most pups are raised in a social group. However, in situations where puppies are isolated from other dogs, and are raised alone, without experiences in canine society, they can fail to learn the give and take of normal puppies.  That's one reason that the dog or older puppy adopted from a shelter or obtained from a private seller can pose problems to a new owner. Brought out on a leash in streets where other dogs go by, or let off a leash in a dog park or outdoor space where other dogs are free, a poorly socialized dog may attack other dogs out of fear. Once grown, such pups most often can never be successfully integrated into a group of dogs.
[[Image:Cachorro.jpg|thumb|right|250px|The archetypal "friendly dog" appearance]]


Human medications should not be given to a dog as a substitute for their regular medication as some can be especially [[toxic]], especially [[paracetamol]]/acetaminophen (Tylenol).
Dogs fill a variety of [[role]]s in [[human society]] and are often trained as [[working dog]]s. Thousands of dogs throughout the world actively [[herding dog|herd]] [[sheep]] and [[cattle]], [[guard dog|guard]] people and property, and guide the [[blindness|blind]] and disabled. Dogs are an important part of [[search and rescue dog|rescue]] work in [[natural disaster]]s. Their noses aid police and military searches for weapons, drugs, and other contraband. However, the most common (and perhaps most important) role of dogs in many countries is as a human companion.
[[Alcoholic beverage]]s pose much of the same hazards to dogs as they do to humans.


Dogs may also find some poisons attractive, including [[antifreeze]], [[snail]] bait, [[insect]] bait, and [[rodent]] poisons. [[Antifreeze]] may be one of the most insidious of poisons to dogs because of its sweet taste and because a dog may walk upon or lie down upon a spill of it or its residue and then lick it off. Dogs must be kept strictly away from antifreeze and not allowed access to any place that has had a spill of it that has not been completely removed.
==Dog breeds==
[[Image:Shar pei welpen.jpg|thumb|left|250px|Shar Peis are known for their characteristic wrinkles, which is one of their many attributes]]


Plants such as [[caladium]], [[dieffenbachia]] and [[philodendron]] will cause [[throat]] irritations that will burn the throat going down as well as coming up. [[Hops]] are particularly dangerous and even small quantities can lead to [[malignant hyperthermia]]. <ref>{{cite journal | first = K. L.| last = Duncan | coauthors = W. R. Hare and W. B. Buck | date = 1997-01-01 | title = Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs | journal = Journal of the American Veterinary Medical Association | volume = 210 | issue = 1 | pages = 51-4 | id = {{PMID|8977648}}}}</ref>
Just as one individual animal might have a combination of traits that causes that particular dog to appear so different from another, there are diverse ''[[Dog breed|breed]]s '' of dogs, where each breed includes dogs that are very similar to each other, but distinct in some identifiable manner from the dogs of a different breed. Through the years, by [[selective breeding|concentrating particular genes and reducing other ones]], breeds have developed in which each member shares a recognizable "brand" of canine style.


[[Amaryllis]], [[daffodil]], [[english ivy]], [[Iris (plant)|iris]], and [[tulip]] (especially the bulbs) cause [[gastric]] irritation and sometimes [[central nervous system]] excitement followed by [[coma]], and, in severe cases, even death.
In [[kennel club]] terms, purebred dogs are individuals that have been selected to "breed true". That means that a good example of a pure bred (pedigreed) dog ''looks like'' its kind in physical appearance, and ''acts like'' its kind in general temperament and certain behaviors. Generally, two purebred parents of the same breed will always produce a litter of pups that will grow up to be quite like them in looks, temperament, and behavior, as opposed to resembling the types of dogs from which the breed originated. The two Chinese [[Shar Pei]] youngsters pictured at left show the famously loose and wrinkled skin of their kind, but there are many more characteristics that typify that breed, ranging from a blue-black tongue to a calm, confident stance.


Ingesting [[foxglove]], [[lily of the valley]], [[larkspur]] and [[oleander]] can be life threatening because the [[cardiovascular]] system is affected. Equally life threatening is the [[yew]] which affects the nervous system. If any of these plants are ingested, get the dog to a veterinarian immediately.
Dogs have an enormous range of normal height and lean weight. The [[Chihuahua]] is the smallest of the [[purebreed]]s and the [[Irish Wolfhound]] is the largest. Despite the great differences in size between these two extremes, all dogs are the same species and can interbreed successfully, although now, thanks to human intervention and the development of dog breeds, care must be taken to only breed individual dogs that are compatible--the mating of a Chihuahua bitch (female) with a [[Great Dane]], for example, would have disastrous consequences for the health of the female dog. Dogs also have an incredibly broad range of ''coat'' (fur) and skin [[Dog colors|colors and patterns]], skull and face shape, ''pelage'' (fur) length and texture, tail shape and carriage, athletic ability and temperaments. All of these, along with other physical characteristics, are influenced by inherited [[genes]]. Even certain specific complex behaviors (like pointing, or retrieving) appear to be inherited in dogs. The gene pool of domestic dogs is highly diverse.


Many household cleaners such as [[ammonia]], [[bleach]], [[disinfectants]], [[drain cleaner]], [[soap]]s, [[detergent]]s, and other cleaners, [[mothball]]s and [[matches]] are dangerous to dogs, as are cosmetics such as [[deodorant]]s, [[hair coloring]], [[nail polish]] and remover, [[permanent wave|home permanent]] lotion, and [[suntan lotion]].


==Reproduction==
===Registered purebreds===
{{main|Dog reproduction}}
Presently, over [[List of dog breeds|800]] [[dog breed]]s are recognized by [[breed club|breed]] and [[kennel club]]s worldwide. Dogs can be registered with a club and receive certifications (commonly called "papers") that indicate a pedigreed purebred status.
 
====Kennel clubs and their affiliates====
:''For more information, see the articles at [[breed club]] and [[kennel club]]''


==Overpopulation==
In order to qualify for registration, a purebred puppy must have two registered parents of the same breed, and meet the [[breed standard]]: a description of a certain "look" (physical conformation) and other features. This breed standard specifies what features are acceptable, which are preferred, and, sometimes, specifies particular features that, if present, disqualify the dog from being chosen as  best of its kind. For example, an AKC-registered [[bulldog]] with the preferred face, ears, stance, size, and most other qualities of the breed, in an AKC-sanctioned confirmation show, would still be disqualified if it had a "brown or liver-colored nose" [http://www.akc.org/breeds/bulldog/index.cfm?SEARCH_BUTTON.X=15\&SEARCH_BUTTON.Y=10].  
According to the Humane Society of the United States, 3-4 million dogs and cats are euthanized each year in the United States and many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or neutering dogs helps keep overpopulation down.[http://www.spayusa.org/main_directory/02-facts_and_education/stats_surveys/javma_articles/02dogs-cats-sterilized.asp] Local humane societies, SPCA's and other animal protection organizations urge people to spay or neuter their pets and to adopt animals from shelters instead of purchasing them. Several notable public figures have spoken out against animal over population, including [[Bob Barker#Animal rights|Bob Barker]]. On his [[game show]], [[The Price is Right]], Barker stressed the issue every episode by stating: "Help control the pet population. Have your pets spayed or neutered."


==Dog health==
Each large kennel club hosts [[dog show]]s in which points are given for how well an individual dog compares to the breed standard, as compared to others of its type displayed at the same show. The male and female dogs competing in the top kennel clubs must be non-sterilized ("entire") animals and, although the gait and demeanor of the dog is evaluated as each walks around the show ring, the major emphasis is on body features. These contests are sometimes called conformational shows.
{{main|Dog health}}
{{further|[[:Category:Dog health]]}}


Dogs are susceptible to various diseases, ailments, and poisons, some of which affect humans in the same way, others of which are unique to dogs. Dogs, like all mammals, are also susceptible to heat exhaustion when dealing with high levels of humidity and/or extreme temperatures.<ref>{{cite web|url=http://www2.dasnr.okstate.edu/index.php?option=com_content&task=view&id=257&Itemid=103 |title=Summer heat can be tough on pets |accessdate=2006-08-21 | first = Trisha | last = Gedon | date = 2006-05-25 | work = Division of Agricultural Sciences and Natural Resources | publisher = Oklahoma State University }}</ref>
Increasingly, kennel clubs are catering to dogs and their owners through various shows and events other than conformational shows. The [[United Kennel Club]] was an innovator in this area; now such disciplines as agility, tracking, herding and carting are regularly sponsored by the [[American Kennel Club]] and others. Dogs may enter these shows and events whether or not they have been sterilized, and some of these events can include non-registered dogs and crossbreds as well.


===Diseases===
Infectious diseases commonly associated with dogs include [[rabies]] (hydrophobia), [[canine parvovirus]], and [[canine distemper]]. Congenital diseases of dogs can include a wide range from hip dysplasia and medial patellar luxation to epilepsy and [[pulmonic stenosis]]. Canines can get just about anything a human can get (excluding many infections which are species specific) like hypothyroidism, cancer, dental disease, heart disease, etc.


===Parasites===  
====Working dog organizations and registries====
Common external parasites are various species of [[flea]]s, [[tick]]s, and [[mites]]. Internal parasites include [[hookworm]]s, [[tapeworm]]s, [[roundworm]]s, and [[heartworms]].
Other breeders concentrate on achieving uniform inherited behavioral traits in the dogs they produce. Some consider conformational traits important but secondary, some do not consider a dog's appearance at all, although this is rarer. Working, hunting, and herding dogs raised by field breeders sometimes only generally resemble the breed standard in appearance, but are more likely to be consistent in doing the job. <!--The phrase "that dog don't hunt" comes from the rural United States and refers to a hunting dog that lacks the finer instincts of its breed --more specific, please, a reference to a group or territory where this is used, e.g.?-->


===Common physical disorders===
====Independent breed clubs====
Some breeds of dogs are also prone to certain genetic ailments, such as [[hip dysplasia]], [[luxating patella]]s, [[cleft palate]], [[blindness]], or [[hearing impairment|deafness]]. Dogs are also susceptible to the same ailments that humans are, including [[Diabetes in cats and dogs|diabetes]], [[epilepsy]], [[cancer]], and [[arthritis]]. [[Gastric torsion]] and [[bloat]] is a dangerous problem in some large-chested breeds.
These may include breeds-in-development, breeds recognized in only one country, and breeds where there are differences in type from the variety of the breed recognized by kennel clubs and their affiliates.


===Lifespan===
===Natural breeds===
{{main|Dog years}}
In some parts of the world the isolation of dogs by geography (islands, mountain passes) has produced so-called natural breeds. These dogs are largely the product of [[natural selection]]. Members of a ''natural breed'' [[true breeding (animals)|breed true]] - adults are similar to each other in appearance and behavior, and produce litters of puppies that not only grow up to resemble their parents, but - once grown, can between themselves propagate more litters of the breed.  The [[Thai Bangkaew Dog]] is an example of a dog breed believed to have developed through isolation.
The typical lifespan of dogs varies considerably by breed. For example, many giant dog breeds average only 7 or 8 years, while some small terrier breeds might live as long as 20 years.The average lifespan for mixed-breed and midsize dogs is about 13 to 14 years. The longest-lived dog with reliable documentation died at 29 in 1939.
Although the lifespans of all living species are mostly uncontrollable, one can significantly extend a dog's life by feeding it the right kinds of foods, giving it exercise, visiting the vet frequently, caring for its special needs, and loving it.


==Behavior==
Sometimes these natural breeds have also undergone selective breeding by humans who desired a certain type of working dog. Such ancient working breeds include the [[Greyhound]], the [[Mastiff]] and the [[Anatolian Shepherd Dog]].  Natural breeds made up many of the very first of the registered breeds, and also include some of the most recent additions to the list of breeds officially recognized by kennel clubs.  ''Breed Recognition'' refers to the fact that a kennel club has officially acknowledged that the breed of dog has been shown to meet the requirements of the particular kennel club.  This has nothing to do with the breed’s actual purebred status and the date of official recognition may have no relation to how long the breed has been known to be in existence.  The Shar Pei is a natural breed, "having existed for centuries in the southern provinces of China, apparently to the [[Han dynasty]], circa 200 BC".<ref>Source for quote: ''Chinese Shar-Pei'' in The Complete Dog Book, Official Publication of the American Kennel Club, 20th Edition, Ballantine Books, New York, 2006,page 543</ref> Despite the fact that statues of dogs that look just like the Shar Pei date back to the Thirteenth Century, the breed was not actually “recognized” until the later part of the Twentieth Century (initially by the Hong Kong Kennel Club).  Other natural breeds have never been recognized formally by any kennel club.
:''For details, see [[:Category:Dog training and behavior]].''


Dogs are very social animals, but this varies on how a dog is treated by its owners and other people it may be around (examples: kindness and nonaggression, physical abuse, starvation, etc.) It is not uncommon for dogs to [[dog attack|attack]] humans and other animals.
===Crossbreds===
:''See the main article at [[mixed-breed dog]].''
Crossbreds or crossbreeds can be loosely defined as animals with at least one known pure breed in its parentage.  Crosses between purebreds have been used (along with mixed-breed crosses) to establish most of the long recognized dog breeds.  This notwithstanding, today's animal welfare advocates have openly deplored this method for any ''current'' propagation of a new breed. That's because it necessarily produces generations of mixed-breed puppies in a world where there is already a great overpopulation of such dogs.


{{sectstub}}
Nevertheless, there are modern dog breeders who purposely mate dogs of two completely different breeds in order to produce a litter of puppies with a set of desired characteristics that are not fully present in either individual parent. Some reasons for this include protecting a longstanding ''strain'' of dog that is not yet a true breed (a method used for example to gain official recognition for the [[Jack Russell Terrier]], long-established but only officially recognised within the last ten years or so) or in response to changing times (the cross breeding of dogs to introduce the genes for a naturally short tail to a traditionally docked breed, in reponse to anti tail-docking legislation, for example).  Crossbreeds in development are sometimes ''called'' a breed colloquially, but do not fulfill the requirement of "[[true breeding|breeding true]]". It takes many generations of careful matings, and much disappointment along the way, to arrive at a bona fide new breed.


==Ancestry and history of domestication==
Although the hybrid puppies in the cross between two purebreds (in breeders' terms, the [[F1 generation]]) often all look alike, these puppies ''cannot'' grow up and be mated to other dogs that were born of the same crossed parentage and reliably produce new puppies that are like them.  
{{main|Origin of the domestic dog}}
[[Image:DogMosaic wb.jpg|thumb|This ancient mosaic, likely Roman, shows a large dog with a collar hunting a lion.]]
[[Molecular systematics]] indicate that the domestic dog (''Canis lupus familiaris'') descends from one or more populations of wild wolves (''Canis lupus''). As reflected in the [[nomenclature]], dogs are descended from the wolf and are able to interbreed with wolves.


The relationship between human and canine has deep roots. [[Wolf]] remains have been found in association with [[Hominidae|hominid]] remains dating from 400,000 years ago. Converging archaeological and genetic evidence indicate a time of [[domestication]] in the late [[Upper Paleolithic]] close to the [[Pleistocene]]/[[Holocene]] boundary, between 17,000 and 14,000 years ago. [[Fossil]] bone morphologies and genetic analysis of current and ancient dog and wolf populations have not yet been able to conclusively determine whether all dogs descend from a single domestication event, or whether dogs were domesticated independently in more than one location. Domesticated dogs may have interbred with local populations of wild wolves on several occasions (so-called introgression).
The breeders of notable crosses such as Cocker Spaniel-Poodle crosses, “Cockapoos” and Labrador Retriever–Poodle crosses “Labradoodles”, point out that development of a new breed is a worthy goal, and that, with ethical breeding practices, all puppies can be properly placed. In addition, some large commercial breeding operations that supply [[hybrid]] dogs claim to sell their puppies to pet shops under an agreement that every puppy is to be sterilized and therefore cannot ever used for breeding, this helps reduce indiscriminate breeding.


The earliest dog fossils, two [[skull|crania]] from [[Russia]] and a [[mandible]] from [[Germany]], date from 13,000 to 17,000 years ago. Their likely ancestor is the large northern [[Holarctic]] wolf, ''Canis lupus lupus''. Remains of smaller dogs from [[Mesolithic]] ([[Natufian]]) cave deposits in the [[Middle East]], dated to around 12,000 years ago, have been interpreted as descendants of a lighter Southwest Asian wolf, ''Canis lupus arabs''. [[Rock art]] and skeletal remains indicate that by 14,000 years ago, dogs were present from [[North Africa]] across [[Eurasia]] to [[North America]]. Dog burials at the [[Mesolithic]] cemetery of [[Svaerdborg]] in Denmark suggest that in ancient Europe dogs were valued companions.
===Mixed breeds (mongrels)===
[[Image:PICT1094.JPG|thumb|right|250px|Mongrels, dogs of uncertain lineage, offer their owners the same qualities that have come to be associated with pet dogs.]]  


Genetic analyses have so far yielded divergent results. Vilà, Savolainen, and colleagues (1997) concluded that dogs split off from wolves between 75,000 and 135,000 years ago, while a subsequent analysis by Savolainen et al. (2002) indicated a "common origin from a single gene pool for all dog populations" between 40,000 and 15,000 years ago in [[East Asia]]. Verginelli et al. (2005), however, suggest both sets of dates must be reevaluated in light of recent findings showing that poorly calibrated molecular clocks have systematically overestimated the age of geologically recent events. On balance, and in agreement with the archaeological evidence, 15,000 years ago is the most likely time for the wolf-dog divergence.
Dogs that came from parents who were not of any pure breed, or whose bloodlines comprise more than one breed, are called ''mongrels'', ''mutts'', or mixed-breed dogs. There are many other names for them, with varying levels of acceptability. The word ‘’mongrel’’, generally taken to be the correct formal word in dog fancy, is considered insulting by some dog lovers. That's probably because, in the English language, this word has sub-meanings that imply a lesser worth.  However, it is fair to say that all dogs are derived from mongrels, and many scientists believe that in the absence of selective breeding, the dog would revert to the little brown [[pariah dog]] believed to be its most recent ancestor. Even the staunch proponents of purebreds generally agree that as pets, mixed-breed dogs offer their owners the same qualities of loyalty, intelligence and companionship that have come to be associated with dogs.


Verginelli examined ancient [[DNA]] evidence from five prehistoric Italian [[canids]] carbon-dated to between 15,000 and 3,000 years old, 341 wolves from several populations worldwide, and 547 purebred dogs. Their results indicate multiple independent origins of dogs and/or of frequent interbreeding between early proto-dogs and wolves throughout a vast geographic range. The detailed history remains unexplored and until further evidence is available, the following section on wolf ancestors must be considered purely speculative.
==Behavior, temperament, and skills==
[[Image:Schulhund-ina-in-schulklasse.jpg|thumb|right|250px|Dogs with special training can aid school children in learning social skills and provide stimulation for elderly patients in nursing homes.]]
===Intelligence===
:''See the main article at [[Dog intelligence]] for more information.''
Both [[anecdotal evidence]] and [[Scientific method|scientific research]] suggest that dogs have a reasonably high intelligence. This intelligence is expressed differently in different breeds and individuals, along with sets of specific behaviors and talents that appear to be inherited. Optimal socialization and training of an individual dog is partly dependent on its own intelligence, inherited behaviors, and temperament.


===Wolf ancestors===
===Natural behaviour===
Although all wolves belong to the species ''[[Gray Wolf|Canis lupus]]'', there are (or were) many subspecies that had developed a distinctive appearance, social structure, and other traits. For example, the [[Japanese Wolf]] and the [[Eastern Timber Wolf]] possess different distinctive coloration, hunting and social structures.
The qualities characterized under the categories ehaviour and temperament can have overlapping elements.  These are related to intelligence, instinct and individual ability.  They are often shaped by a dog’s individual personality and can be modified by training.
The [[Indian Wolf]] is thought to have contributed to the development of more breeds of dogs than other subspecies. Many of today's wild dogs, such as the [[dingo]] and the [[pariah dog]]s, are descended from this wolf.
:''See main article at [[Dog behaviour]]''
*instinctive herding
*instinctively chasing prey animals
*innate cleanliness, such as not fouling the “nest”.  This is often found in natural breeds.
===Temperament===
*dog-on-dog aggression – A few breeds cannot help having this inborn trait and their breed standards allow it. The [[Rottweiler]] is an example.  This is a natural behaviour and should not be confused with dog-on-human aggression.
*inherent gentleness - This is characteristic of breeds such as the [[Labrador Retriever]]
*dog-on-human aggression – this is almost universally condemned. In [[show dog]]s, aggression against humans results in immediately dismissal from the show ring.  (The dog is said to be “excused”.) Note that this undesirable trait should not be confused with the assertiveness acquired in the training of military and [[police dog]]s.
*observable loyalty – Loyalty is universally associated with dogs, but breeds such as the [[Miniature Fox Terrier]] are so particularly noted for it that this trait is written into the breed standard.


The [[Indian Wolf]] is also thought to have bred with descendants of the European wolf to create the [[Mastiff]]s and eventually leading to the development of such diverse breeds as the [[Pug]], the [[St. Bernard (dog)|Saint Bernard]], and the [[Bloodhound]]. The [[Tibetan Mastiff]] is an example of an ancient breed.


The [[European wolf]], in turn, may have contributed many of its attributes to the [[Spitz]] dog types, most [[terrier]]s, and many of today's [[sheepdog]]s. The [[Chinese wolf]] is probably ancestor to the [[Pekingese]] and toy [[spaniel]]s, although it is also probable that descendants of the Chinese and European wolves encountered each other over the millennia, contributing to many of the oriental [[toy dog|toy]] breeds.
===Special skills and ability===
*speed – as exhibited by Greyhounds and [[Whippet]]s, for example
*endurance -  the [[Australian Kelpie]]’s breed standard requires that the dog gives the impression of having great stamina
*swimming - [[Gun dog]]s, a large category encompassing several groups, each containing many breeds, are often exceptional swimmers.
*intelligence - Dog intelligence is usually taken as a given, but breeds such as the [[German Shepherd Dog]], the [[Border Collie]] and the [[Poodle]] have tested exceptionally high in this regard and proven highly trainable.
*jumping - The Border Collie is such a good jumper that some trial clubs hold separate contests for them out of fairness to other breeds.  The [[Jack Russell Terrier]] is noted for its ability to jump very high, disproportionately to its height.
*exceptional sight, smell or hearing - The [[bloodhound]] is an example.
===Training===
Formal training in [[dog obedience|obedience]] and other disciplines is offered by many kennel clubs and private training organizations.


The [[Eastern Timber Wolf]] is a direct ancestor to most, if not all, of the North American northern [[sled dog]] types. This interbreeding still occurs with dogs living in the [[Arctic]] region, where the attributes of the wolf that enable survival in a hostile environment are valued by humans. Additionally, unintentional crossbreeding occurs simply because dogs and wolves live in the same environment. The general [[reproductive isolation]] which is required to define dogs and wolves as separate species is purely a result of lack of opportunity, stemming from a general mutual unfamiliarity, suspicion, mistrust, and fear.
Police and military organizations typically run their own specialized training or contract with specialists expert in this exacting work. These are typically referred to as K-9 (canine) units, where dogs are trained to sniff out drugs or explosives, rescue trapped or lost people, or attack on command. These are often considered on a par with their human handlers in many respects; for example, when one dies or is killed in action, they are accorded full ceremonial funerals.


The [[phenotype|phenotypic]] characteristics that distinguish a wolf from a dog are tenuous. Wolves typically have a "brush tail" and erect ears. While some dog breeds possess one of these characteristics, they rarely possess both.
Since socialization to people and other dogs is part of the general training of puppies, many of the specialized training programs designed for dogs are given in classes. Not only do the dogs learn the skills taught, but they also learn to interact properly in a group situation.


===Speed of domestication===
==Diet==
Current research indicates that domestication, or the attributes of a domesticated animal, can occur much more quickly<ref>http://www.amsci.org/amsci/articles/99articles/Trut.html#26879</ref> than previously believed. Domestication of a wild dog may occur within one or two human generations with deliberate [[selective breeding]]. It is also now generally believed that initial domestication was through mutual desire. Wild canines who scavenged around human habitations received more food than their more skittish or fearful counterparts. Canines who attacked people or their children were likely killed or driven away, while those more friendly animals survived. Canines would have been beneficial by chasing away other [[vermin]] or [[scavengers]]. With their sharp senses, they would also be valuable as an alarm against marauding predators. The relationship is theorized to have developed in this way.
If given the opportunity, dogs are [[omnivore]]s, eating [[plant]] materials and animals. Generally, dogs will both scavenge carcasses and kill and eat animal prey.


===Dog meat for human consumption=== 
Just as there are schools of thought about human [[diet]], with advocates of various strict regimens ranging from macrobiotics to raw foods, there are a number of diets recommended for dogs that involve an entire philosophy of dog health. The [[BARF]] diet is one with a large following.  There are breeders who insist that puppies purchased from them be maintained on particular diets, and generally their wishes should be respected.
''Main article: [[Dog meat]]''


In a number of countries around the world, apart from being kept as pets, certain breeds of dogs are [[slaughter]]ed as a source of meat and specifically raised on farms for that purpose. In countries where dogs are particularly popular as household pets, the use of dogs as a source of food is often considered a taboo and abhorrent cultural practice, although there are exceptions such as [[Vietnam]] where dogs are popular as pets and as meat.{{fact}}
When purchasing a puppy from a breeder, or adopting from a shelter, it is wise to find out the diet that the animal has been maintained on, and to make only gradual changes.


===Dog Abuse===  
It is probably best to feed dogs a varied diet, supplemented with [[vitamin]]s or high-quality commercial dog food.  Most standard dog care guides stress that dogs should not be fed table scraps. This is because cooked [[bone]]s can splinter internally, human food recipes can contain substances harmful for dogs, such as [[onion]]s, and the [[fat]] in most table scraps is not any better for dogs than for people.  In any case, there are widely-varying opinions and dogs have been known to do well on commercial food, raw food, home-cooked food, or, when their health requires it, special or restricted diets.  When in doubt, dog owners should be guided by the advise of a [[veterinarian]].
{{main|Cruelty to animals}}
Cruelty to dogs refers to treatment which causes unacceptable suffering or [[harm]]. What qualifies as unacceptable suffering varies depending on the country and its culture. <ref>http://www.pet-abuse.com/</ref>
In the developed world, excessive fat is a problem for many dogs. [[Obese pets|Obese dogs]] can have health problems, and can benefit from restriction of calories in the diet and from increased exercise. Puppies, especially large and giant breed puppies, can suffer joint problems if fed too much highly nutritious food early on. <!--I am not sure what the original author was trying to say with this sentence: "That's because puppies can reach, or at least approach, their adult weight by 6 months to 12 months of age, and if that adult weight and size is large, the bones may not have a chance to strengthen suitably to offer healthy support."  Can someone rephrase?-->


==Famous dogs==
==Dog health==
Dogs are susceptible to various diseases, ailments, and poisons, some of which affect humans in the same way, others of which are unique to dogs. Dogs, like all mammals, are also susceptible to heat exhaustion when dealing with high levels of humidity and/or extreme temperatures.<ref>{{cite web|url=http://www2.dasnr.okstate.edu/index.php?option=com_content&task=view&id=257&Itemid=103 |title=Summer heat can be tough on pets |accessdate=2006-08-21 | first = Trisha | last = Gedon | date = 2006-05-25 | work = Division of Agricultural Sciences and Natural Resources | publisher = Oklahoma State University }}</ref>


The long shared history of dogs and humans has resulted in many [[List of famous dogs|individual dogs achieving fame]] or notoriety, and many [[list of fictional dogs|fictional dogs]] have been created for literature, cinema, and elsewhere.
===Diseases===
Most diseases are species-specific; so generally the diseases that affect dogs cannot be transmitted to humans, and vice versa.  [[Rabies]] is an exception to this rule (see below).  (Compare this with [[parasite]]s, many of which ''can'' be transmitted between species.) Infectious diseases commonly associated with dogs include [[rabies]] (hydrophobia), [[canine parvovirus]], and [[canine distemper]]. Congenital diseases of dogs can include a wide range from hip dysplasia and medial patellar luxation to epilepsy and [[pulmonic stenosis]]. Except for the many infections which are species specific, dogs are susceptible to the same ailments that humans are, including [[Diabetes in cats and dogs|diabetes]], [[epilepsy]], hypothyroidism, dental disease, heart disease, [[cancer]], and [[arthritis]].


==Dog breeds==
===Vaccinations===
[[Image:Jack_11-24-05_1106AM.jpg|thumb|200px|left|A [[Jack Russell Terrier]] playing with his toy.]]
[[Image:Roodog2k-ivan-and-boxer.JPG|thumb|The dog has developed into hundreds of breeds with a great degree of variation, such as this [[Miniature Pinscher]] and [[Boxer (dog)|Boxer]].]]
[[Image:Trippadorable.jpg|right|thumb|200px|A [[Maltese (dog)|Maltese]] enjoying the fall leaves.]]
There are numerous [[dog breed]]s, with [[List of dog breeds|over 800]] being recognized by various [[kennel club]]s worldwide. As all dog breeds have been derived from mixed-breed dog populations, the term "purebred" has meaning only with respect to a certain number of generations. Many dogs, especially outside the United States and Western Europe, belong to no recognized breed.


A few basic [[:Category:Dog types|breed types]] have evolved gradually during the domesticated dog's relationship with man over the last 10,000 or more years, but most modern breeds are of relatively recent derivation. Many of these are the product of a deliberate process of [[artificial selection]]. Because of this, some breeds are highly specialized, and there is extraordinary morphological diversity across different breeds. Despite these differences, dogs are able to distinguish dogs from other kinds of animal.
Immunizations are available for many of the infectious diseases that affect dogs. Some of these diseases are passed from dog to dog, others to dogs through insects. [[vaccination|Vaccinations]] for canine distemper, [[hepatitis]], [[leptospirosis]], [[parainfluenza]], [[canine parvovirus]], [[Lyme disease]] and [[rabies]] are available. Some of these are combined in "one shot", and one - rabies - is often legally required of dog owners to provide for their dogs. That's because rabies is a fatal disease that can be transmitted by the bite of an infected dog.


The definition of a dog breed is a matter of some controversy. Depending on the size of the original founding population, closed gene pool breeds can have problems with inbreeding, specifically due to [[founder effect]]. Dog breeders are increasingly aware of the importance of population genetics and of maintaining diverse gene pools. Health testing and new DNA tests can help avoid problems, by providing a replacement for natural selection. Without selection, inbreeding and closed gene pools can increase the risk of severe health or behavioural problems. Some organizations define a breed more loosely, such that an individual may be considered of one breed as long as 75% of its parentage is of that breed. These considerations affect both pets and the show dogs entered in [[conformation show|dog shows]]. Even prize-winning [[purebred]] dogs sometimes possess crippling [[Genetic disorder|genetic defects]] due to founder effect or [[inbreeding]].<ref>Pages 57 to 72, Chapter Four, "Hereditary Problems in Purebred Dogs",''The Puppy Report: How to Select a Healthy, Happy Dog'', Larry Shook, Ballantine, 1995, mass market paperback, 130 pages, ISBN 0-345-38439-3</ref> These problems are not limited to [[purebred]] dogs and can affect mixed-breed populations. <ref>Larry Shook, the author of ''The Puppy Report: How to Select a Healthy, Happy Dog'', Pages 13 to 34, Chapter Two, "Breeders Can Hazardous to Health",''The Puppy Report: How to Select a Healthy, Happy Dog'', Larry Shook, Ballantine, 1995, mass market paperback, 130 pages, ISBN 0-345-38439-3</ref> The behavior and appearance of a dog of a particular breed can be predicted fairly accurately, while mixed-breed dogs show a broader range of innovative appearance and behavior.
Some of these illnesses are only prevalent in certain regions of the world, and the selection of which immunizations is important varies according to geography.


[[Image:Staffordshire Bull Terrier - Labrador Cross.JPG|left|thumb|200px|A 10-year-old [[Staffordshire Bull Terrier]]/[[Labrador Retriever|Labrador]] cross enjoys the sunlight.]]
===Parasites: treatment and prevention===
Unlike diseases, some parasites can be passed between dogs and humans.  Common external [[parasite]]s are various species of [[flea]]s, [[tick]]s, and [[mites]]. Internal parasites include [[hookworm]]s, [[tapeworm]]s, [[roundworm]]s, and [[heartworms]].


In February 2004, the Canine Studies Institute in [[Aurora, Ohio]], arranged recognized breeds of dogs into ten categories.  
Generally, prevention of these parasites involves the administration of a systemic medicine or the use of applied chemicals through the wearing of collars or other means.


[[Mixed-breed dog]]s or [[Mongrel]]s are dogs that do not belong to specific breeds, being mixtures of two or more in variant percentages. Mixed breeds, or dogs with no purebred ancestry, are not inherently "better" or "worse" than purebred dogs as companions, [[pet]]s, [[working dog]]s, or competitors in [[dog sports]]. Sometimes mixed-breed dogs are deliberately bred, for example, the Cockapoo, a mixture of Cocker Spaniel and Miniature [[Poodle]]. Such deliberate crosses may display [[hybrid vigor]] and other desirable traits, but can also lack one or more of the desired traits of their parents, such as temperament or a particular color or coat. However, without genetic testing of the parents, the crosses can sometimes end up inheriting genetic defects that occur in both parental breeds. Deliberately crossing two or more breeds is also a manner of establishing new breeds.
===Common genetic disorders===
Some categories of dogs are especially prone to certain genetic ailments, such as [[hip dysplasia]], [[luxating patella]]e or [[cleft palate]].  Occasionally genetic disorders can be  breed-related: [[blindness]] and [[hearing impairment|deafness]] are disorders than have been linked to [[gene]]s in specific breeds. [[Gastric torsion]] and [[bloat]] is a dangerous problem in some large-chested breeds.


===Neoteny in the rapid evolution of diverse dog breeds===
===Lifespan===
This rapid evolution of dogs from wolves is an example of [[neoteny]] or [[pedomorphosis|paedomorphism]]. As with many species, the young wolves are more social and less [[dominant]] than adults; therefore, the selection for these characteristics, whether deliberate or inadvertent, is more likely to result in a simple retention of juvenile characteristics into adulthood than to generate a complex of independent new changes in behavior. (This is true of many domesticated animals, including human beings themselves, who have many characteristics similar to young [[bonobo]].) This paedomorphic selection naturally results in a retention of juvenile physical characteristics as well. Compared to wolves, many adult dog breeds retain such juvenile characteristics as soft fuzzy fur, round torsos, large heads and eyes, ears that hang down rather than stand erect, etc.; characteristics which are shared by most juvenile [[mammal]]s, and therefore generally elicit some degree of protective and nurturing behavior cross-species from most adult mammals, including humans, who term such characteristics "cute" or "appealing".


The example of canine neoteny goes even further, in that the various breeds are differently neotenized according to the type of behavior that was selected.[http://books.google.com/books?id=_kOoVw0SIhUC&pg=PA394&lpg=PA394&vq=neotenous+behavior&dq=%22Gould%22+%22Eight+Little+Piggies:+Reflections+in+Natural+History%22+&sig=Q1iF36A6ieMKgh3eRAtSeDKTydQ Stephen Jay Gould; Eight Little Piggies: Reflections in Natural History; W. W. Norton & Company, 1993; pp. 394]
The typical lifespan of dogs varies considerably by breed, and seems to be somewhat related to size. For example, many giant dog breeds average only 7 or 8 years, while some small terrier breeds might live as long as 20 years.The average lifespan for mixed-breed and midsize dogs is about 13 to 14 years.


* [[Livestock guardian dog]]s retain the most juvenile characteristics: they stay close to home with their foster "litter" (which might include a flock of [[domestic sheep|sheep]]), rather than going out hunting, they have almost no predatory behavior (which would be disastrous in the vicinity of such a natural prey stimulus as sheep), they respond to perceived threats with a lot of vocalization and attempts to alert and engage the dominant individuals in their "pack" (''i.e.'' humans) whenever possible, engaging in actual combat only as a last resort. In addition, they retain very juvenile physical characteristics such as round bodies and heads, soft coats, ears that hang down, and so on, which do not elicit fear responses from the sheep in the way that an appearance similar to that of an adult wolf would. (Compare to the physical appearance of the [[border collie]], a sheep [[herding]] dog, whose physical configuration is closer to that of an adult wild canine and who therefore has a greater capacity to frighten sheep into a desired pattern of movement, along with the more adult aggressive temperament to do so).
==Other dog-human issues==
* [[Gun dog]] breeds used in hunting&mdash;that is, [[pointer (dog)|pointers]], [[setter]]s, [[spaniel]]s, and [[retriever]]s&mdash;have an intermediate degree of paedomorphism; they are at the point where they share in the pack's hunting behavior, but are still in a junior role, not participating in the actual attack. They identify potential prey and freeze into immobility, for instance, but refrain from then stalking the prey as an adult predator would do next; this results in the "pointing" behavior for which such dogs are bred. Similarly, they seize dead or wounded prey and bring it back to the "pack", even though they did not attack it themselves, that is, "retrieving" behavior. Their physical characteristics are closer to that of the mature wild canine than the sheepdog breeds, but they typically do not have erect ears, etc.
===Choosing and caring for dogs===
* [[Scenthound]]s maintain an intermediate body type and behavior pattern that causes them to actually pursue prey by tracking their scent, but tend to refrain from actual individual attacks in favor of vocally summoning the pack leaders (in this case, humans) to do the job. They often have a characteristic vocalization called a bay. Some examples are the Beagle, Bloodhound, Basset Hound, Coonhound, Dachshund, Fox Hound, Otter Hound, and Harrier.
There is no hard-and fast rule for the choosing of a pet. Among the many decisions that has to be made are whether to pick a purebred, crossbred or mutt, and what the individual can afford. Besides the initial outlay, the maintenance of dogs can be costly: food, shelter, training, health and dental care, emergency services, and boarding or home care all have to be considered.  Dog owner's should be aware that, like humans, there are higher costs at the early and latter stages of a dog's life, when they have specialized needs.
* [[Sighthound]]s, who pursue and attack perceived prey on sight, maintain the mature canine size and some features, such as narrow chest and lean bodies, but have largely lost the erect ears of the wolf and thick double layered coats. Some examples are the Afghan, Borzoi, Saluki, Sloughi, Pharaoh Hound, Azawakh, Whippet, and Greyhound.
* [[Mastiff]]-types are large dogs, both tall and massive with barrel-like chests, large bones, and thick skulls.  They have traditionally been bred for war, protection, and guardian work.
* [[Bulldog]]-types are medium sized dogs bred for combat against both wild and domesticated animals. These dogs have a massive, square skull and large bones with an extremely muscular build and broad shoulders.
* [[Terrier]]s similarly have adult aggressive behavior, famously coupled with a lack of juvenile submission, and display correspondingly adult physical features such as erect ears, although many breeds have also been selected for size and sometimes [[achondroplasia|dwarfed legs]] to enable them to pursue prey in their burrows.


The least paedomorphic behavior pattern may be that of the [[basenji]], bred in [[Africa]] to hunt alongside humans almost on a peer basis; this breed is often described as highly independent, neither needing nor appreciating a great deal of human attention or nurturing, often described as "catlike" in its behavior. It too has the body plan of an adult canine predator.
In addition, owners should give consideration to what will happen to the dog in the event of the human's incapcity or death, and custody of family dogs in the event of divorce or separation.
Of course, dogs in general possess a significant ability to modify their behavior according to experience, including adapting to the behavior of their "pack leaders"&mdash;again, humans. This allows them to be trained to behave in a way that is not specifically the most natural to their breed; nevertheless, the accumulated experience of thousands of years shows that some combinations of nature and nurture are quite daunting, for instance, training [[whippet]]s to guard flocks of sheep.


===Breed popularity===
Almost every breed of dog has an organized group of fanciers promoting it. Doing an internet search on the breed will yield a number of breeder sites, along with the various fanciers' organizations' web sites. Usually, one or more of the sites will list not only the attributes that are wonderful features of the breed, but any special health problems along with information for diagnosis and treatment.
Breed popularity varies widely over time<ref>http://www.slate.com/id/2122298/</ref> and in different parts of the world and different segments of the population. Counting by [[AKC]] registration (not by [[dog licence|licensing registration]] or by [[United Kennel Club|UKC]] registration, which could present different statistics), the [[Labrador Retriever]] has been the United States's most commonly registered breed of dog since 1991<ref>http://www.akc.org/news/index.cfm?article_id=2389</ref>. However, even within parts of the United States, popularity varies; for example, in 2005 the most-registered breed in New York City was the [[Poodle]]; the [[Yorkshire Terrier]] was the second-most-registered breed in [[Houston]] but didn't even make the top ten in [[Honolulu]]<ref>http://www.akc.org/reg/topdogsbycity.cfm</ref>. However, animal shelters in many parts of the United States report that the most-commonly available dog for adoption is the [[American Pit Bull Terrier]] or pit bull-type mixes, making up as much as 20% of dogs available for adoption, none of which would be registered with the AKC.<ref>http://www.aspca.org/site/PageServer?pagename=cruelty_pitbull</ref> Two decades ago, in 1983, the AKC's top two registered breeds were the [[American Cocker Spaniel]] and the [[Poodle]].<ref>{{cite book|title=World Almanac and Book of Facts|year=1985|publisher=Newspaper Enterprise Association (Doubleday)}}</ref>


In [[Britain]], [[The Kennel Club]] reports that the most-registered breed from at least 1999 to 2005 was the Labrador Retriever. It rounds out the top three for 1999 to 2005 with the [[German Shepherd Dog]], also popular in the States, and the [[English Cocker Spaniel]]<ref>http://www.the-kennel-club.org.uk/pressoffice/press_top20.html</ref>, which is no longer even in the top ten in the States.
Finally, it is probably best to give some thought to the final disposition of the remains of a deceased dog, so that those decisions do not have to be made when one is grieving for a lost friend.


==See also==
===Overpopulation===
* [[Puppy]]
According to the Humane Society of the United States, 3-4 million dogs and cats are euthanized each year in the United States and many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or neutering dogs helps keep overpopulation down.[http://www.spayusa.org/main_directory/02-facts_and_education/stats_surveys/javma_articles/02dogs-cats-sterilized.asp] Local humane societies, [[Society for the Prevention of Cruelty to Animals|SPCAs]] and other animal protection organizations urge people to spay or neuter their pets and to adopt animals from shelters instead of purchasing them.
* [[Dog communication]]
* [[Dog licence]]
* [[Bark (dog)]]
* [[List of dog breeds]]
* [[Dog attack]]


==References ==
===Dog/Wolf hybrids===
<references />


==Further reading==
In the wild, in areas where wolves still roam but the human population is also established, there is the occasional inter-breeding of wolf and dog. Since a wolf pack is not likely to perceive a dog as anything but prey, and a domestic dog is unlikely to survive attack from even a lone wolf, this is not as common as the interbreeding of dogs and [[coyote]]s in similar circumstances. When dogs and coyotes do interbreed in the wild, the resulting hybrids often fail to thrive because they lack behavior features of the wild canine parent. For example, the domestic bitch ordinarily comes into heat twice or more times a year, where as the coyote female is fertile only once a year. The timing of the dog's estrus does not correspond to the local seasons in a way that is advantageous to a newborn litter, and so puppies born in the lean times of winter or drought are more likely to die. The instinct to only allow one mating pair of animals in the pack and the nurturing instincts of other pack members ( including the males) towards that pair's pups, is almost completely lost in the dog; and so hybrids in the wild are less able to raise litters that survive.
* Abrantes, Roger (1999). ''Dogs Home Alone''. Wakan Tanka, 46 pages. ISBN 0-9660484-2-3 (paperback).
[[Image:Wolf dog.jpg|right|thumb|250px|{{#ifexist:Template:Wolf dog.jpg/credit|{{Wolf dog.jpg/credit}}<br/>|}}A dog/wolf hybrid.]]
* A&E Television Networks (1998). ''Big Dogs, Little Dogs: The companion volume to the A&E special presentation'', A Lookout Book, GT Publishing. ISBN 1-57719-353-9 (hardcover).
In human society, there are people who selectively breed wolves and dogs as pets. In many areas, there are currently laws against keeping wolves in captivity, but there are regions where this is not the case. Often, the breeder of these hybrids works not from full wolves, but selects a hybrid wolf/dog as one parent, and either another hybrid or a domestic dog as the other parent.  
* Alderton, David (1984). ''The Dog'', Chartwell Books. ISBN 0-89009-786-0.
* Brewer, Douglas J. (2002) ''Dogs in Antiquity: Anubis to Cerberus: The Origins of the Domestic Dog'', Aris & Phillips ISBN 0-85668-704-9
* Coppinger, Raymond and Lorna Coppinger (2002). ''Dogs: A New Understanding of Canine Origin, Behavior and Evolution'', University of Chicago Press ISBN 0-226-11563-1
*Cunliffe, Juliette (2004). ''The Encyclopedia of Dog Breeds''. Parragon Publishing. ISBN 0-7525-8276-3.
* Derr, Mark (2004). ''Dog's Best Friend: Annals of the Dog-Human Relationship''. University of Chicago Press. ISBN 0-226-14280-9
* Donaldson, Jean (1997). ''The Culture Clash''. James & Kenneth Publishers. ISBN 1-888047-05-4 (paperback).
*Fogle, Bruce, DVM (2000). ''The New Encyclopedia of the Dog''. Doring Kindersley (DK). ISBN 0-7894-6130-7.
*Grenier, Roger (2000). ''The Difficulty of Being a Dog''. University of Chicago Press. ISBN 0-226-30828-6
* Milani, Myrna M. (1986). ''The Body Language and Emotion of Dogs: A practical guide to the Physical and Behavioral Displays Owners and Dogs Exchange and How to Use Them to Create a Lasting Bond'', William Morrow, 283 pages. ISBN 0-688-12841-6 (trade paperback).
* Pfaffenberger, Clare (1971). ''New Knowledge of Dog Behavior''. Wiley, ISBN 0-87605-704-0 (hardcover); Dogwise Publications, 2001, 208 pages, ISBN 1-929242-04-2 (paperback).
* Savolainen, P. et al. (2002). Genetic Evidence for an East Asian Origin of Domestic Dogs. ''Science'' '''298'''. 5598: 1610&ndash;1613.
* Shook, Larry (1995). "Breeders Can Hazardous to Health", ''The Puppy Report: How to Select a Healthy, Happy Dog'', Chapter Two, pp. 13&ndash;34. Ballantine, 130 pages, ISBN 0-345-38439-3 (mass market paperback); Globe Pequot, 1992, ISBN 1-55821-140-3 (hardcover; this is much cheaper should you buy).
* Shook, Larry (1995). ''The Puppy Report: How to Select a Healthy, Happy Dog'', Chapter Four, "Hereditary Problems in Purebred Dogs", pp. 57&ndash;72. Ballantine, 130 pages, ISBN 0-345-38439-3 (mass market paperback); Globe Pequot, 1992, ISBN 1-55821-140-3 (hardcover; this is much cheaper should you buy).
* Thomas, Elizabeth Marshall (1993). ''The Hidden Life of Dogs'' (hardcover), A Peter Davison Book, Houghton Mifflin. ISBN 0-395-66958-8.
* Verginelli, F. et al. (2005). Mitochondrial DNA from Prehistoric Canids Highlights Relationships Between Dogs and South-East European Wolves. ''Mol. Biol. Evol.'' '''22''': 2541&ndash;2551.
* Vilà, C. et al. (1997). [http://www.mnh.si.edu/GeneticsLab/StaffPage/MaldonadoJ/PublicationsCV/Science_Dog_Paper.pdf Multiple and ancient origins of the domestic dog.] ''Science'' '''276''':1687&ndash;1689. (Also [http://www.idir.net/~wolf2dog/wayne1.htm "Multiple and Ancient Origins of the Domestic Dog"])
*''Small animal internal medicine'', RW Nelson, Couto page 107


==External links==
Molecular genetic research has shown that dogs appear to have been domesticated from wolves, but not from wolves in general - instead, selected individual ancient wolves were kept and interbred. There is speculation that among the wolves that harried these early human settlements or frequented ancient dumps, the particular individuals chosen for "adoption" by people were probably not only very young - but were exceptionally "nice". There is variation in behavioral characteristics of individual members in every large group of wolves. It is not likely that the wild wolf pup who is at the extreme for aggressiveness, for example, would be tolerated in human society - once grown into an adult wolf, even if originally adopted in its infancy.
{{sisterlinks|Dog}}
{{Wikispecies}}


*[http://www.akc.org/ American Kennel Club]
That has been the overall situation with wolf/dog hybrids. Even if carefully raised from birth, some adult wolf/dogs do not remain "tame" enough to safely interact with people. Breeders of wolf/dog hybrids routinely remove the puppies from the mother by 2-3 weeks of age, and hand raise them, bottle feeding the puppies every few hours. Each puppy is allowed contact with at least one other puppy, but all puppies are kept isolated from adult dogs and wolves (including their own mother) because if they are allowed contact they usually will not bond to their human handlers. That, of course, is not the case in pure domestic dog puppies, who can ordinarily be raised in the home with free access to both mother and human companions. Even with special nurturing of wolf/dog pups, and even though these hybrid puppies are usually much less than 50% wolf, there is an extremely high rate of attacks on humans by adult hybrid wolf/dogs - including the members of the human family that raised them. Breeders of hybrid wolf/dogs counsel that these dogs must ''at all times'' be fenced off from any possible contact with strangers [http://www.wolfpark.org/wolfdogs/guidelines.html]. Fatal human attacks by hybrids are not rare, and often victimize children.
*[http://www.ankc.aust.com/breed_list.html Australian National Kennel Club]
*[http://www.ckc.ca/ Canadian Kennel Club]
*[http://www.fci.be Fédération Cynologique Internationale (FCI) - World Canine Organisation]
*[http://www.dogdomain.com/fci-1.htm FCI International breed standards]
*[http://www.the-kennel-club.org.uk The Kennel Club (UK)]
*[http://www.nzkc.org.nz/dogselect.html New Zealand Kennel Club]


<!-- interwiki -->
==Notable dogs==
: ''A selected listing of dogs whose names have become recorded in history.  None of the following dogs are fictional, and each of them helps illustrate the range of accomplishments of working and companion dogs.  See the full article at: [[famous dogs]].''


[[Category:Dog health| ]]
{{r|Barry (dog)}}
[[Category:Dogs| ]]
{{r|Balto}}
{{r|Brandy (dog)}}
{{r|Greyfriars Bobby}}
{{r|Hachiko}}
{{r|Rin Tin Tin}}


[[af:Hond]]
==Notes and references ==
[[ar:كلب]]
<references />
[[an:Can]]
[[ast:Perru]]
[[bm:Wùlù]]
[[zh-min-nan:Káu]]
[[bo:ཁྱི་]]
[[bg:Домашно куче]]
[[ca:Gos]]
[[cs:Pes domácí]]
[[cy:Ci]]
[[da:Hund]]
[[de:Haushund]]
[[et:Koer]]
[[el:Σκύλος]]
[[es:Perro]]
[[eo:Hundo]]
[[eu:Txakur]]
[[fa:سگ]]
[[fr:Chien]]
[[gd:Cù]]
[[gl:Can]]
[[got:𐌷𐌿𐌽𐌳𐍃]]
[[ko:개]]
[[hr:Domaći pas]]
[[io:Hundo]]
[[id:Anjing]]
[[ia:Can]]
[[it:Canis lupus familiaris]]
[[he:כלב]]
[[jv:Asu]]
[[ka:ძაღლი]]
[[la:Canis]]
[[lv:Suns]]
[[lb:Haushond]]
[[lt:Šuo]]
[[hu:Kutya]]
[[ms:Anjing]]
[[nl:Hond]]
[[nds-nl:Hond]]
[[ja:イヌ]]
[[no:Tamhund]]
[[nn:Hund]]
[[nrm:Tchian]]
[[oc:Ca]]
[[ug:ئىت]]
[[pl:Pies domowy]]
[[pt:Cão]]
[[ro:Câine]]
[[ru:Собака домашняя]]
[[simple:Dog]]
[[sk:Pes domáci]]
[[sl:Pes]]
[[sr:Пас]]
[[sh:Pas]]
[[fi:Koira]]
[[sv:Hund]]
[[ta:நாய்]]
[[th:สุนัข]]
[[vi:Chó]]
[[chr:ᎩᏟ]]
[[tr:Köpek]]
[[uk:Собака]]
[[zh:犬]]

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Domestic dog
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
Species: C. lupus
Subspecies: C. l. familiaris
Trinomial name
Canis lupus familiaris[1]

Dogs are domesticated canines that have been closely associated with humans ever since they first evolved from gray wolves several thousand years ago. Throughout the world dogs are still intimately associated with humans in a variety of roles, and because of this they are often called "man's best friend". Today they are nearly ubiquitous, as household pets, cherished companions, full-time workers, and even, in some cultures, as food.

Dogs and people may communicate better with each other than any other two species.[2] Dogs and humans understand each other on a basic level: we are able to interpret the dog's instinctive body language (along with canine vocalizations like the growl and whine); and the dog, in turn, has an innate ability to respond appropriately both to human body language, as well as to the emotional tone of the human voice. Some research suggests that dogs may be better at interpreting cues from humans than even our closest relatives, the chimpanzees. [3]People can be educated beyond these basics to manage their dogs more precisely, and dogs can be trained to be extremely responsive to people. In addition, dogs can modify the behaviour of their humans to a surprising degree.

The origin of the dog

Ancestry

By the mid-20th Century, scientists had generally agreed that the immediate ancestor of the dog must be one of its close living relatives: jackals, coyotes or wolves, but they had trouble deciding on which one.[4] Most early research depended on archeological evidence to try to solve the riddle of the dog's origin.

This issue was finally solved using DNA which proved that the Gray Wolf is the sole ancestor of all modern dogs.[5][6] Therefore, dogs are a subspecies (Canis lupus familiaris) of the Gray Wolf (Canis lupus).[7] The most likely ancestors are Asian populations of the wolves, based on the diversity of comparing the genetic diversity of Asian wolves with that of modern dog breeds [5] while the data is consistent with multiple domestication events. [5][6]

The domestication of the dog

Through the 1970s and 1980s, schoolchildren were taught that humans domesticated the dog. Nowadays, many scientists feel that a more accurate description would be that the relationship evolved on a more equal footing, with humans and dogs coming together to ensure their mutual survival in a hostile environment. Another way of looking at the question would be to ask if the domestication of the dog was a result of natural selection, in which nature plays the larger part in deciding which dogs survive; in this case the dogs which adapted most readily to humans in their environment, or of artificial selection--humans picking which dogs contributed to the gene pool based on which had traits humans found desirable--the precursor of selective breeding. Surveys and analysis have made cases for both theories. [8]

The history of the relationship between humans and dogs

The relationship between humans and dogs is certainly an ancient one. Cave paintings such as one found in Tassili n'Ajjer suggest that primitive man and dog were already living in harmony. [9] Dogs in such images are portrayed as hunters, both in the company of humans and alone, which can be taken as an indication of a developed relationship. Precise dates for these drawings are frequently debated, as they existed before recorded history, and our dating techniques can be affected by many factors, but some of this rock art is several thousand years old. The earliest known domestic dog remains "may date back as far as 10,000 BC, preceding the Neolithic period....evidence indicates that dogs were kept in Jericho by 6500 BC." [10]

By the time of the pharaohs, dogs had already established their value as workers and human companions. Egyptian paintings show that selective breeding had already begun; sighthounds were clearly identified. Dog mummies have been found in the tombs of Pharaohs. The Assyrians, Greeks and Romans all used dogs for hunting and as battle companions. Pliny the Elder described the value of dogs in no uncertain terms, and also referred to the existence of--if not refined dog breeds, certainly defined dog types.[11] [12] [13] A Chinese ceramic statue from the era of the T'ang Dynasty, circa 700 A.D., depicts a dog bearing a resemblance to today's Dandie Dinmont Terrier. [14]

By the medieval period, hunters had classified dogs according to the type of game they were best suited to handle.[15]. By the 16th Century, Of Englische Dogges, the first written work specifically and exclusively about dogs, appeared. [16] Illustrations in The Hunt of the Unicorn, a series of medieval tapestries attributed as Flemish, circa 1500, show many domesticated hunting dogs, including hounds and terriers, and one somewhat like a Great Dane. [17]

Dog anatomy and health

Modern dog breeds show more variation in size, appearance, and behavior than any other domestic animal.

Even a friendly dog has sharp teeth.

Physical characteristics

Dogs generally share attributes with their wild ancestors, the wolves. Dogs are both predators and scavengers, possessing sharp teeth and strong jaws for attacking, holding, and tearing their food. Although selective breeding has changed the appearance of many breeds, all dogs retain basic traits from their distant ancestors. Like many other predatory mammals, the dog has powerful muscles, fused wrist bones, a cardiovascular system that supports both sprinting and endurance, and teeth for catching and tearing. Compared to the bone structure of the human foot, dogs technically walk on their toes.

Sight

Because the lenses of dogs' eyes are flatter than humans', they cannot see as much detail; on the other hand, their eyes are more sensitive to light and motion than humans' eyes. Some dogs, the sight hounds, have been specifically bred to capitalize on their use of vision in tracking prey. These breeds include the Greyhound and Afghan Hound.[18] The most capable sighthounds have a field of vision up to 270° (compared to 180° for humans). Broad-headed dog breeds with forward set eyes have a much narrower field of vision, sometimes no wider than the human 180 degrees.

Hearing

Dogs detect sounds as low as the 16 to 20 Hz frequency range (compared to 20 to 70 Hz for humans) and as high as 70 kHz to 100 kHz (compared to 13 to 20 kHz for humans), and in addition have a degree of ear mobility that helps them to rapidly pinpoint the exact location of a sound. Eighteen or more muscles can tilt, rotate and raise or lower a dog's ear. The dog's sensitivity to even very quiet sounds, as compared to a human’s, means that a dog can identify a sound's location much faster, as well as hear sounds that are coming from far more distant sources than a human companion by its side.[19]

Those with more open ear shapes, like the erect ears of wild canids like the fox, generally hear better than those with the floppier ears of many domesticated species.

Smell

Dogs have nearly 220 million smell-sensitive cells over an area about the size of a pocket handkerchief (compared to 5 million over an area the size of a postage stamp for humans). It is fair to say that all dogs have a richer olfactory experience than ours. Some breeds have been selectively bred for excellence in detecting scents, over and above their canine brethren, such as the scent hounds, including and particularly Bloodhounds.

Reproduction

The dog's reproductive cycle

See the main article at dog reproduction.

Bitches (female dogs) have a reproductive cycle that generally varies from six months to one year, although there are bitches that come into oestrus more or less frequently. This season is the only time that bitches are receptive to mating.

Gestation, the period in which mammals carry their developing young in the uterus, lasts about two months (60-64 days). Whelping (the birth of puppies) usually takes place without incident. The dam (mother) ordinarily gives birth to more than one puppy at a time. The group of pups born together is known as a litter.

Unlike human females, bitches remain fertile throughout their adult lives.

Dog breeding

See the main article at dog breeding.

Dog breeders mate selected dogs together hoping to reproduce desired traits in the resulting offspring. Those who breed working dogs, such as herders, pick breeding stock that have instincts and abilities suited to the tasks the dogs are required to perform. By contrast, people who breed show dogs have strict sets of criteria to conform to; these are largely related to the dog's appearance and personality.

Formal dog organisations record purebred dogs in breed registries.

Dogs and humans in daily life

Some dog owners view their pets as fully-fledged family members, and most dogs are able to act the part. That ability stems from two basic sources: (1) the "hard-wiring" of the dog's behavior (programmed by its canine genes), and (2) the individual dog's experience with people. Dogs are, like humans, highly social animals. Although the instincts to behave in ways that ease interactions in the pack are inborn in all normal dogs, the right early experiences are critical if puppies are to grow up into companionable dogs. Those "right" experiences have everything to do with contact with people and with other dogs, and they must occur early in the dog's life - probably before the puppy reaches 12 weeks of age.

(CC) Photo: Bev Sykes
Puppies are rarely born singly; the group of puppies born together is known as a litter.

When puppies are raised with plenty of close contact to people and to other dogs, they become fully socialized. Socialized pups seem to view their human companions as members of their pack, and make few, if any, distinctions between their owners and fellow dogs. As these puppies mature, they can be taught to modify their behavior towards people, and treat their human companions more gently than their canine ones. Puppies who are raised without human nurturing have a harder time adjusting to interactions with owners once they have passed the critical period of about 3 months of age, no matter how much gentle attention is then given them. Orphaned puppies that are bottle fed and raised by humans alone, without any contact to any other dog or puppy, are in danger of becoming abnormally fixated on humans, and such puppies include animals that turn their attentions, sexual and social, to people instead of to dogs. Mounting behavior, for example is an annoyance to visitors and an embarrassment for owners. It not only signals sexual attention, but is a normal part of a dog's dominance behaviour, a tool for determining pack hierarchy. Proper dog-human socialization establishes the human's position as pack leader early, and eliminates the need for such trials.

The group of puppies born together is called a litter. That means that most pups are raised in a social group. However, in situations where puppies are isolated from other dogs, and are raised alone, without experiences in canine society, they can fail to learn the give and take of normal puppies. That's one reason that the dog or older puppy adopted from a shelter or obtained from a private seller can pose problems to a new owner. Brought out on a leash in streets where other dogs go by, or let off a leash in a dog park or outdoor space where other dogs are free, a poorly socialized dog may attack other dogs out of fear. Once grown, such pups most often can never be successfully integrated into a group of dogs.

The archetypal "friendly dog" appearance

Dogs fill a variety of roles in human society and are often trained as working dogs. Thousands of dogs throughout the world actively herd sheep and cattle, guard people and property, and guide the blind and disabled. Dogs are an important part of rescue work in natural disasters. Their noses aid police and military searches for weapons, drugs, and other contraband. However, the most common (and perhaps most important) role of dogs in many countries is as a human companion.

Dog breeds

Shar Peis are known for their characteristic wrinkles, which is one of their many attributes

Just as one individual animal might have a combination of traits that causes that particular dog to appear so different from another, there are diverse breeds of dogs, where each breed includes dogs that are very similar to each other, but distinct in some identifiable manner from the dogs of a different breed. Through the years, by concentrating particular genes and reducing other ones, breeds have developed in which each member shares a recognizable "brand" of canine style.

In kennel club terms, purebred dogs are individuals that have been selected to "breed true". That means that a good example of a pure bred (pedigreed) dog looks like its kind in physical appearance, and acts like its kind in general temperament and certain behaviors. Generally, two purebred parents of the same breed will always produce a litter of pups that will grow up to be quite like them in looks, temperament, and behavior, as opposed to resembling the types of dogs from which the breed originated. The two Chinese Shar Pei youngsters pictured at left show the famously loose and wrinkled skin of their kind, but there are many more characteristics that typify that breed, ranging from a blue-black tongue to a calm, confident stance.

Dogs have an enormous range of normal height and lean weight. The Chihuahua is the smallest of the purebreeds and the Irish Wolfhound is the largest. Despite the great differences in size between these two extremes, all dogs are the same species and can interbreed successfully, although now, thanks to human intervention and the development of dog breeds, care must be taken to only breed individual dogs that are compatible--the mating of a Chihuahua bitch (female) with a Great Dane, for example, would have disastrous consequences for the health of the female dog. Dogs also have an incredibly broad range of coat (fur) and skin colors and patterns, skull and face shape, pelage (fur) length and texture, tail shape and carriage, athletic ability and temperaments. All of these, along with other physical characteristics, are influenced by inherited genes. Even certain specific complex behaviors (like pointing, or retrieving) appear to be inherited in dogs. The gene pool of domestic dogs is highly diverse.


Registered purebreds

Presently, over 800 dog breeds are recognized by breed and kennel clubs worldwide. Dogs can be registered with a club and receive certifications (commonly called "papers") that indicate a pedigreed purebred status.

Kennel clubs and their affiliates

For more information, see the articles at breed club and kennel club

In order to qualify for registration, a purebred puppy must have two registered parents of the same breed, and meet the breed standard: a description of a certain "look" (physical conformation) and other features. This breed standard specifies what features are acceptable, which are preferred, and, sometimes, specifies particular features that, if present, disqualify the dog from being chosen as best of its kind. For example, an AKC-registered bulldog with the preferred face, ears, stance, size, and most other qualities of the breed, in an AKC-sanctioned confirmation show, would still be disqualified if it had a "brown or liver-colored nose" [2].

Each large kennel club hosts dog shows in which points are given for how well an individual dog compares to the breed standard, as compared to others of its type displayed at the same show. The male and female dogs competing in the top kennel clubs must be non-sterilized ("entire") animals and, although the gait and demeanor of the dog is evaluated as each walks around the show ring, the major emphasis is on body features. These contests are sometimes called conformational shows.

Increasingly, kennel clubs are catering to dogs and their owners through various shows and events other than conformational shows. The United Kennel Club was an innovator in this area; now such disciplines as agility, tracking, herding and carting are regularly sponsored by the American Kennel Club and others. Dogs may enter these shows and events whether or not they have been sterilized, and some of these events can include non-registered dogs and crossbreds as well.


Working dog organizations and registries

Other breeders concentrate on achieving uniform inherited behavioral traits in the dogs they produce. Some consider conformational traits important but secondary, some do not consider a dog's appearance at all, although this is rarer. Working, hunting, and herding dogs raised by field breeders sometimes only generally resemble the breed standard in appearance, but are more likely to be consistent in doing the job.

Independent breed clubs

These may include breeds-in-development, breeds recognized in only one country, and breeds where there are differences in type from the variety of the breed recognized by kennel clubs and their affiliates.

Natural breeds

In some parts of the world the isolation of dogs by geography (islands, mountain passes) has produced so-called natural breeds. These dogs are largely the product of natural selection. Members of a natural breed breed true - adults are similar to each other in appearance and behavior, and produce litters of puppies that not only grow up to resemble their parents, but - once grown, can between themselves propagate more litters of the breed. The Thai Bangkaew Dog is an example of a dog breed believed to have developed through isolation.

Sometimes these natural breeds have also undergone selective breeding by humans who desired a certain type of working dog. Such ancient working breeds include the Greyhound, the Mastiff and the Anatolian Shepherd Dog. Natural breeds made up many of the very first of the registered breeds, and also include some of the most recent additions to the list of breeds officially recognized by kennel clubs. Breed Recognition refers to the fact that a kennel club has officially acknowledged that the breed of dog has been shown to meet the requirements of the particular kennel club. This has nothing to do with the breed’s actual purebred status and the date of official recognition may have no relation to how long the breed has been known to be in existence. The Shar Pei is a natural breed, "having existed for centuries in the southern provinces of China, apparently to the Han dynasty, circa 200 BC".[20] Despite the fact that statues of dogs that look just like the Shar Pei date back to the Thirteenth Century, the breed was not actually “recognized” until the later part of the Twentieth Century (initially by the Hong Kong Kennel Club). Other natural breeds have never been recognized formally by any kennel club.

Crossbreds

See the main article at mixed-breed dog.

Crossbreds or crossbreeds can be loosely defined as animals with at least one known pure breed in its parentage. Crosses between purebreds have been used (along with mixed-breed crosses) to establish most of the long recognized dog breeds. This notwithstanding, today's animal welfare advocates have openly deplored this method for any current propagation of a new breed. That's because it necessarily produces generations of mixed-breed puppies in a world where there is already a great overpopulation of such dogs.

Nevertheless, there are modern dog breeders who purposely mate dogs of two completely different breeds in order to produce a litter of puppies with a set of desired characteristics that are not fully present in either individual parent. Some reasons for this include protecting a longstanding strain of dog that is not yet a true breed (a method used for example to gain official recognition for the Jack Russell Terrier, long-established but only officially recognised within the last ten years or so) or in response to changing times (the cross breeding of dogs to introduce the genes for a naturally short tail to a traditionally docked breed, in reponse to anti tail-docking legislation, for example). Crossbreeds in development are sometimes called a breed colloquially, but do not fulfill the requirement of "breeding true". It takes many generations of careful matings, and much disappointment along the way, to arrive at a bona fide new breed.

Although the hybrid puppies in the cross between two purebreds (in breeders' terms, the F1 generation) often all look alike, these puppies cannot grow up and be mated to other dogs that were born of the same crossed parentage and reliably produce new puppies that are like them.

The breeders of notable crosses such as Cocker Spaniel-Poodle crosses, “Cockapoos” and Labrador Retriever–Poodle crosses “Labradoodles”, point out that development of a new breed is a worthy goal, and that, with ethical breeding practices, all puppies can be properly placed. In addition, some large commercial breeding operations that supply hybrid dogs claim to sell their puppies to pet shops under an agreement that every puppy is to be sterilized and therefore cannot ever used for breeding, this helps reduce indiscriminate breeding.

Mixed breeds (mongrels)

Mongrels, dogs of uncertain lineage, offer their owners the same qualities that have come to be associated with pet dogs.

Dogs that came from parents who were not of any pure breed, or whose bloodlines comprise more than one breed, are called mongrels, mutts, or mixed-breed dogs. There are many other names for them, with varying levels of acceptability. The word ‘’mongrel’’, generally taken to be the correct formal word in dog fancy, is considered insulting by some dog lovers. That's probably because, in the English language, this word has sub-meanings that imply a lesser worth. However, it is fair to say that all dogs are derived from mongrels, and many scientists believe that in the absence of selective breeding, the dog would revert to the little brown pariah dog believed to be its most recent ancestor. Even the staunch proponents of purebreds generally agree that as pets, mixed-breed dogs offer their owners the same qualities of loyalty, intelligence and companionship that have come to be associated with dogs.

Behavior, temperament, and skills

Dogs with special training can aid school children in learning social skills and provide stimulation for elderly patients in nursing homes.

Intelligence

See the main article at Dog intelligence for more information.

Both anecdotal evidence and scientific research suggest that dogs have a reasonably high intelligence. This intelligence is expressed differently in different breeds and individuals, along with sets of specific behaviors and talents that appear to be inherited. Optimal socialization and training of an individual dog is partly dependent on its own intelligence, inherited behaviors, and temperament.

Natural behaviour

The qualities characterized under the categories ehaviour and temperament can have overlapping elements. These are related to intelligence, instinct and individual ability. They are often shaped by a dog’s individual personality and can be modified by training.

See main article at Dog behaviour
  • instinctive herding
  • instinctively chasing prey animals
  • innate cleanliness, such as not fouling the “nest”. This is often found in natural breeds.

Temperament

  • dog-on-dog aggression – A few breeds cannot help having this inborn trait and their breed standards allow it. The Rottweiler is an example. This is a natural behaviour and should not be confused with dog-on-human aggression.
  • inherent gentleness - This is characteristic of breeds such as the Labrador Retriever
  • dog-on-human aggression – this is almost universally condemned. In show dogs, aggression against humans results in immediately dismissal from the show ring. (The dog is said to be “excused”.) Note that this undesirable trait should not be confused with the assertiveness acquired in the training of military and police dogs.
  • observable loyalty – Loyalty is universally associated with dogs, but breeds such as the Miniature Fox Terrier are so particularly noted for it that this trait is written into the breed standard.


Special skills and ability

  • speed – as exhibited by Greyhounds and Whippets, for example
  • endurance - the Australian Kelpie’s breed standard requires that the dog gives the impression of having great stamina
  • swimming - Gun dogs, a large category encompassing several groups, each containing many breeds, are often exceptional swimmers.
  • intelligence - Dog intelligence is usually taken as a given, but breeds such as the German Shepherd Dog, the Border Collie and the Poodle have tested exceptionally high in this regard and proven highly trainable.
  • jumping - The Border Collie is such a good jumper that some trial clubs hold separate contests for them out of fairness to other breeds. The Jack Russell Terrier is noted for its ability to jump very high, disproportionately to its height.
  • exceptional sight, smell or hearing - The bloodhound is an example.

Training

Formal training in obedience and other disciplines is offered by many kennel clubs and private training organizations.

Police and military organizations typically run their own specialized training or contract with specialists expert in this exacting work. These are typically referred to as K-9 (canine) units, where dogs are trained to sniff out drugs or explosives, rescue trapped or lost people, or attack on command. These are often considered on a par with their human handlers in many respects; for example, when one dies or is killed in action, they are accorded full ceremonial funerals.

Since socialization to people and other dogs is part of the general training of puppies, many of the specialized training programs designed for dogs are given in classes. Not only do the dogs learn the skills taught, but they also learn to interact properly in a group situation.

Diet

If given the opportunity, dogs are omnivores, eating plant materials and animals. Generally, dogs will both scavenge carcasses and kill and eat animal prey.

Just as there are schools of thought about human diet, with advocates of various strict regimens ranging from macrobiotics to raw foods, there are a number of diets recommended for dogs that involve an entire philosophy of dog health. The BARF diet is one with a large following. There are breeders who insist that puppies purchased from them be maintained on particular diets, and generally their wishes should be respected.

When purchasing a puppy from a breeder, or adopting from a shelter, it is wise to find out the diet that the animal has been maintained on, and to make only gradual changes.

It is probably best to feed dogs a varied diet, supplemented with vitamins or high-quality commercial dog food. Most standard dog care guides stress that dogs should not be fed table scraps. This is because cooked bones can splinter internally, human food recipes can contain substances harmful for dogs, such as onions, and the fat in most table scraps is not any better for dogs than for people. In any case, there are widely-varying opinions and dogs have been known to do well on commercial food, raw food, home-cooked food, or, when their health requires it, special or restricted diets. When in doubt, dog owners should be guided by the advise of a veterinarian.

In the developed world, excessive fat is a problem for many dogs. Obese dogs can have health problems, and can benefit from restriction of calories in the diet and from increased exercise. Puppies, especially large and giant breed puppies, can suffer joint problems if fed too much highly nutritious food early on.

Dog health

Dogs are susceptible to various diseases, ailments, and poisons, some of which affect humans in the same way, others of which are unique to dogs. Dogs, like all mammals, are also susceptible to heat exhaustion when dealing with high levels of humidity and/or extreme temperatures.[21]

Diseases

Most diseases are species-specific; so generally the diseases that affect dogs cannot be transmitted to humans, and vice versa. Rabies is an exception to this rule (see below). (Compare this with parasites, many of which can be transmitted between species.) Infectious diseases commonly associated with dogs include rabies (hydrophobia), canine parvovirus, and canine distemper. Congenital diseases of dogs can include a wide range from hip dysplasia and medial patellar luxation to epilepsy and pulmonic stenosis. Except for the many infections which are species specific, dogs are susceptible to the same ailments that humans are, including diabetes, epilepsy, hypothyroidism, dental disease, heart disease, cancer, and arthritis.

Vaccinations

Immunizations are available for many of the infectious diseases that affect dogs. Some of these diseases are passed from dog to dog, others to dogs through insects. Vaccinations for canine distemper, hepatitis, leptospirosis, parainfluenza, canine parvovirus, Lyme disease and rabies are available. Some of these are combined in "one shot", and one - rabies - is often legally required of dog owners to provide for their dogs. That's because rabies is a fatal disease that can be transmitted by the bite of an infected dog.

Some of these illnesses are only prevalent in certain regions of the world, and the selection of which immunizations is important varies according to geography.

Parasites: treatment and prevention

Unlike diseases, some parasites can be passed between dogs and humans. Common external parasites are various species of fleas, ticks, and mites. Internal parasites include hookworms, tapeworms, roundworms, and heartworms.

Generally, prevention of these parasites involves the administration of a systemic medicine or the use of applied chemicals through the wearing of collars or other means.

Common genetic disorders

Some categories of dogs are especially prone to certain genetic ailments, such as hip dysplasia, luxating patellae or cleft palate. Occasionally genetic disorders can be breed-related: blindness and deafness are disorders than have been linked to genes in specific breeds. Gastric torsion and bloat is a dangerous problem in some large-chested breeds.

Lifespan

The typical lifespan of dogs varies considerably by breed, and seems to be somewhat related to size. For example, many giant dog breeds average only 7 or 8 years, while some small terrier breeds might live as long as 20 years.The average lifespan for mixed-breed and midsize dogs is about 13 to 14 years.

Other dog-human issues

Choosing and caring for dogs

There is no hard-and fast rule for the choosing of a pet. Among the many decisions that has to be made are whether to pick a purebred, crossbred or mutt, and what the individual can afford. Besides the initial outlay, the maintenance of dogs can be costly: food, shelter, training, health and dental care, emergency services, and boarding or home care all have to be considered. Dog owner's should be aware that, like humans, there are higher costs at the early and latter stages of a dog's life, when they have specialized needs.

In addition, owners should give consideration to what will happen to the dog in the event of the human's incapcity or death, and custody of family dogs in the event of divorce or separation.

Almost every breed of dog has an organized group of fanciers promoting it. Doing an internet search on the breed will yield a number of breeder sites, along with the various fanciers' organizations' web sites. Usually, one or more of the sites will list not only the attributes that are wonderful features of the breed, but any special health problems along with information for diagnosis and treatment.

Finally, it is probably best to give some thought to the final disposition of the remains of a deceased dog, so that those decisions do not have to be made when one is grieving for a lost friend.

Overpopulation

According to the Humane Society of the United States, 3-4 million dogs and cats are euthanized each year in the United States and many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or neutering dogs helps keep overpopulation down.[3] Local humane societies, SPCAs and other animal protection organizations urge people to spay or neuter their pets and to adopt animals from shelters instead of purchasing them.

Dog/Wolf hybrids

In the wild, in areas where wolves still roam but the human population is also established, there is the occasional inter-breeding of wolf and dog. Since a wolf pack is not likely to perceive a dog as anything but prey, and a domestic dog is unlikely to survive attack from even a lone wolf, this is not as common as the interbreeding of dogs and coyotes in similar circumstances. When dogs and coyotes do interbreed in the wild, the resulting hybrids often fail to thrive because they lack behavior features of the wild canine parent. For example, the domestic bitch ordinarily comes into heat twice or more times a year, where as the coyote female is fertile only once a year. The timing of the dog's estrus does not correspond to the local seasons in a way that is advantageous to a newborn litter, and so puppies born in the lean times of winter or drought are more likely to die. The instinct to only allow one mating pair of animals in the pack and the nurturing instincts of other pack members ( including the males) towards that pair's pups, is almost completely lost in the dog; and so hybrids in the wild are less able to raise litters that survive.

(CC) Photo: John Paul Schuylkill
A dog/wolf hybrid.

In human society, there are people who selectively breed wolves and dogs as pets. In many areas, there are currently laws against keeping wolves in captivity, but there are regions where this is not the case. Often, the breeder of these hybrids works not from full wolves, but selects a hybrid wolf/dog as one parent, and either another hybrid or a domestic dog as the other parent.

Molecular genetic research has shown that dogs appear to have been domesticated from wolves, but not from wolves in general - instead, selected individual ancient wolves were kept and interbred. There is speculation that among the wolves that harried these early human settlements or frequented ancient dumps, the particular individuals chosen for "adoption" by people were probably not only very young - but were exceptionally "nice". There is variation in behavioral characteristics of individual members in every large group of wolves. It is not likely that the wild wolf pup who is at the extreme for aggressiveness, for example, would be tolerated in human society - once grown into an adult wolf, even if originally adopted in its infancy.

That has been the overall situation with wolf/dog hybrids. Even if carefully raised from birth, some adult wolf/dogs do not remain "tame" enough to safely interact with people. Breeders of wolf/dog hybrids routinely remove the puppies from the mother by 2-3 weeks of age, and hand raise them, bottle feeding the puppies every few hours. Each puppy is allowed contact with at least one other puppy, but all puppies are kept isolated from adult dogs and wolves (including their own mother) because if they are allowed contact they usually will not bond to their human handlers. That, of course, is not the case in pure domestic dog puppies, who can ordinarily be raised in the home with free access to both mother and human companions. Even with special nurturing of wolf/dog pups, and even though these hybrid puppies are usually much less than 50% wolf, there is an extremely high rate of attacks on humans by adult hybrid wolf/dogs - including the members of the human family that raised them. Breeders of hybrid wolf/dogs counsel that these dogs must at all times be fenced off from any possible contact with strangers [4]. Fatal human attacks by hybrids are not rare, and often victimize children.

Notable dogs

A selected listing of dogs whose names have become recorded in history. None of the following dogs are fictional, and each of them helps illustrate the range of accomplishments of working and companion dogs. See the full article at: famous dogs.

Notes and references

  1. ↑ International Commission of Zoological Nomenclature: Opinion 2027: Usage of 17 specific names based on wild species which are pre-dated by or contemporary with those based on domestic animals (Lepidoptera, Osteichthyes, Mammalia): conserved
  2. ↑ Stephen Budiansky, The Truth about Dogs: An Inquiry into Ancestry Social Conventions. Mental Habits Moral Fiber Canis familiaris. 2001 ISBN 014100228X
  3. ↑ In an 2002 article for BBC News Online, Christine McGourty cites two separate American studies, one at Harvard University and the other at the Wolf Hollow Wolf Sanctuary, both in the United States. Puppies were found to be as good as older dogs at finding hidden food using clues from humans. [1] sourced on 7/20/2007.
  4. ↑ Ashworth, Lou Sawyer and Kraft, Irene. The Concise Encyclopedia of Dogs. London: Octopus Books, 1974. pgs. 79-81.
  5. ↑ 5.0 5.1 5.2 Savolainen, P., Y. P. Zhang, J. Luo, J. Lundeberg, and T. Leitner. 2002. Genetic evidence for an East Asian origin of domestic dogs. Science 298:1610-1613.
  6. ↑ 6.0 6.1 Vila, C., P. Savolainen, J. E. Maldonado, I. R. Amorim, J. E. Rice, R. L. Honeycutt, K. A. Crandall, J. Lundeberg, and R. K. Wayne. 1997. Multiple and ancient origins of the domestic dog. Science 276:1687-1689.
  7. ↑ Don E. Wilson & DeeAnn M. Reeder (editors). 2005. Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed), Johns Hopkins University Press, 2,142 pp.
  8. ↑ The idea of the wolf being more proactive in its "domestication" became more seriously discussed in 1he 1990s. From Wolf to Dog New York Times, September 24, 2007, discusses competing theories. Ray and Lorna Coppinger argue in Dogs: A New Understanding of Canine Origin, Behavior and Evolution, that this was natural selection, in which scavenger wolves hung about human encampments; the ones who became less afraid of people got the first pick of human waste (food), and therefore thrived. Wolf to Woof: The Evolution of dogs, National Geographic, January 2002, and Dr Bruce Fogle in The New Encyclopedia of the Dog discuss the same idea. However, the idea that primitive humans selected the tamest wolf cubs and bred like to like over successive generation still has its adherents. Dogs and more dogs, an Affectionate Analysis. Video recording. Nova, WGBH, Boston, 2004.
  9. ↑ The site is referred to as Tessili-n-Ajjer in The Concise Encyclopedia of Dogs op.cit.
  10. ↑ Alderton, David. The Dog: The Complete Guide to Dogs and Their World. London: New Burlington Books, 1987.
  11. ↑ The Concise Encyclopedia of Dogs contains illustrations of domestic dogs from a Minoan painting, circa 2000 B.C. and an Egyptian painting circa 1450 B.C., both depicting hounds, and an Assyrian relief depicting a mastiff type hunting dog in what appears to be a choke collar.
  12. ↑ See for example the bas-relief of Asshurbanipal, c. 2000 B.C. This and a Greek vase showing a depiction of a mythological tale featuring dogs are illustrated in The Dog by Alderton, op. cit.
  13. ↑ Pliny the Elder, Natural History
  14. ↑ The Concise Encyclopedia of Dogs, op. cit.
  15. ↑ Dame Juliana Berners The Boke of St Albans 1496, a hunting reference book.
  16. ↑ Dr John Caius, Of Englische Dogges: Dr Johannes Caius, De Canibus Brittanicus (1570) and translated by Abraham Fleming as Of Englishe Dogges (1576).
  17. ↑ The tapestries are now in The Cloisters museum in New York City. This is also illustrated in Alderton, op. cit.
  18. ↑ Catalyst: Dogs' Eyes. Australian Broadcasting Corporation (2003-09-25). Retrieved on 1st April 2007.
  19. ↑ How well do dogs hear? Accessed 1st April 2007
  20. ↑ Source for quote: Chinese Shar-Pei in The Complete Dog Book, Official Publication of the American Kennel Club, 20th Edition, Ballantine Books, New York, 2006,page 543
  21. ↑ Gedon, Trisha (2006-05-25). Summer heat can be tough on pets. Division of Agricultural Sciences and Natural Resources. Oklahoma State University. Retrieved on 2006-08-21.
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