Domestic Dog
Canis familiaris
Domestic Dog (Canis familiaris) is a species in the genus Canis, family Canidae, order Carnivora.
Scientific classification
| Rank | Taxon |
|---|---|
| Domain | Eukaryota |
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Mammalia |
| Order | Carnivora |
| Family | Canidae |
| Genus | Canis |
| Species | Canis familiaris |
Description
The domestic dog is the most morphologically variable land mammal alive. Adult body mass spans roughly 1 kilogram in a Chihuahua to more than 90 in a mastiff, a fortyfold range with no parallel among wild species, and skull shape ranges from the extreme brachycephaly of a pug to the long narrow rostrum of a borzoi. Nearly all of that variation has arisen in the last few thousand years, and much of it in the last two centuries of formal breed creation.
Beneath the variety, the dog remains a canid: digitigrade, with non-retractile claws, a dentition built for shearing, and an olfactory epithelium far larger than a human's, which supports the scent-tracking work dogs are trained for.
Domestication
Dogs descend from grey wolves and are the first animal humans domesticated — before agriculture, and by a considerable margin. Genetic and archaeological evidence places the split somewhere between roughly 15,000 and 30,000 years ago; the location, the number of separate domestication events, and whether wolves were actively tamed or first self-selected around human refuse remain actively debated.
Whether the dog is a species in its own right or a subspecies of Canis lupus is a matter of taxonomic convention rather than biology. Dogs and wolves interbreed freely and produce fertile offspring. This wiki follows its backbone in treating Canis familiaris as a species; many authorities write Canis lupus familiaris instead.
Behaviour
Dogs read human social cues to an unusual degree. They follow human pointing gestures spontaneously — something even hand-raised wolves and chimpanzees do poorly — and attend to human gaze in ways that suggest selection on social attentiveness during domestication. Working roles built on this include herding, guarding, hunting, sledding, detection of explosives, narcotics and some diseases, and guide work for people with disabilities.
References
- Coppinger, R. and Coppinger, L. (2001). *Dogs: A Startling New Understanding of Canine Origin,
Behavior and Evolution*. Scribner.
- Hare, B. and Tomasello, M. (2005). Human-like social skills in dogs? *Trends in Cognitive
Sciences* 9(9).