The breed with the shortest lifespan (among breeds for which there is a questionnaire survey with a reasonable sample size) is the Dogue de Bordeaux, with a median longevity of about 5.2 years, but several breeds, including miniature bull terriers, bloodhounds, and Irish wolfhounds are nearly as short-lived, with median longevities of 6 to 7 years.
The genetic divergence between dogs and wolves occurred between 40,000–20,000 years ago, just before or during the Last Glacial Maximum. This timespan represents the upper time-limit for the commencement of domestication because it is the time of divergence and not the time of domestication, which occurred later. The domestication of animals commenced over 15,000 years ago, beginning with the grey wolf (Canis lupus) by nomadic hunter-gatherers. The archaeological record and genetic analysis show the remains of the Bonn–Oberkassel dog buried beside humans 14,200 years ago to be the first undisputed dog, with disputed remains occurring 36,000 years ago. It was not until 11,000 years ago that people living in the Near East entered into relationships with wild populations of aurochs, boar, sheep, and goats.
Dogs bear their litters roughly 58 to 68 days after fertilization, with an average of 63 days, although the length of gestation can vary. An average litter consists of about six puppies, though this number may vary widely based on the breed of dog. In general, toy dogs produce from one to four puppies in each litter, while much larger breeds may average as many as twelve.
Español: acicalar a un perro, Português: Cuidar da Higiene do seu Cão, Italiano: Fare la Toeletta al Cane, Deutsch: Fellpflege beim Hund, Русский: сделать груминг собаки, Français: toiletter son chien, 中文: 给狗狗做清洁, Čeština: Jak na hygienu vašeho psa, العربية: الاعتناء بنظافة كلب, Nederlands: De vacht van je hond verzorgen, Tiếng Việt: Vệ sinh cho chó, 日本語: 犬の手入れをする
Clear the dog's eyes. White-haired breeds or those with large eyes that water a lot (Pekingese, Pugs, Pomeranians, etc.) may need more maintenance in this area than others. Depending on your particular dog, this step may be a simple matter of wiping or pulling eye debris away from the corners of the eyes. Long-haired or white-haired dogs may need special attention to make sure that all gunk is out of the coat, as they may get tear stains. You can buy products made for removing "tear stains" from a white coat at a pet supply store.
The domestic dog is the first species, and the only large carnivore, known to have been domesticated. Especially over the past 200 years, dogs have undergone rapid phenotypic change and were formed into today's modern dog breeds due to artificial selection by humans. These breeds can vary in size and weight from a 0.46 kg (1.0 lb) teacup poodle to a 90 kg (200 lb) giant mastiff. Phenotypic variation can include height measured to the withers ranging from 15.2 centimetres (6.0 in) in the Chihuahua to 76 cm (30 in) in the Irish Wolfhound; color varies from white through grays (usually called "blue") to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; coats can be short or long, coarse-haired to wool-like, straight, curly, or smooth. The skull, body, and limb proportions vary significantly between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores. Some breeds demonstrate outstanding skills in herding, retrieving, scent detection, and guarding, which demonstrates the functional and behavioral diversity of dogs. The first dogs were domesticated from shared ancestors of modern wolves, however the phenotypic changes that coincided with the dog–wolf genetic divergence are not known.
^ Jump up to: a b Thalmann, O.; Shapiro, B.; Cui, P.; Schuenemann, V.J.; Sawyer, S.K.; Greenfield, D.L.; Germonpre, M.B.; Sablin, M.V.; Lopez-Giraldez, F.; Domingo-Roura, X.; Napierala, H.; Uerpmann, H.-P.; Loponte, D.M.; Acosta, A.A.; Giemsch, L.; Schmitz, R.W.; Worthington, B.; Buikstra, J.E.; Druzhkova, A.; Graphodatsky, A.S.; Ovodov, N.D.; Wahlberg, N.; Freedman, A.H.; Schweizer, R.M.; Koepfli, K.- P.; Leonard, J.A.; Meyer, M.; Krause, J.; Paabo, S.; et al. (2013). "Complete Mitochondrial Genomes of Ancient Canids Suggest a European Origin of Domestic Dogs". Science. 342 (6160): 871–874. Bibcode:2013Sci...342..871T. doi:10.1126/science.1243650. hdl:10261/88173. PMID 24233726.
In a study of seven breeds of dogs (Bernese mountain dog, basset hound, Cairn terrier, Epagneul Breton, German Shepherd dog, Leonberger, and West Highland white terrier) it was found that inbreeding decreases litter size and survival. Another analysis of data on 42,855 dachshund litters found that as the inbreeding coefficient increased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression. In a study of boxer litters, 22% of puppies died before reaching 7 weeks of age. Stillbirth was the most frequent cause of death, followed by infection. Mortality due to infection increased significantly with increases in inbreeding.
Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and/or external stimuli. As the oldest domesticated species, with estimates ranging from 9,000–30,000 years BCE, the minds of dogs inevitably have been shaped by millennia of contact with humans. As a result of this physical and social evolution, dogs, more than any other species, have acquired the ability to understand and communicate with humans, and they are uniquely attuned to human behaviors. Behavioral scientists have uncovered a surprising set of social-cognitive abilities in the domestic dog. These abilities are not possessed by the dog's closest canine relatives nor by other highly intelligent mammals such as great apes but rather parallel some of the social-cognitive skills of human children.
Where the domestication of the dog took place remains debated, with the most plausible proposals spanning Western Europe, Central Asia and East Asia. This has been made more complicated by the recent proposal that an initial wolf population split into East and West Eurasian groups. These two groups, before going extinct, were domesticated independently into two distinct dog populations between 14,000 and 6,400 years ago. The Western Eurasian dog population was gradually and partially replaced by East Asian dogs introduced by humans at least 6,400 years ago. This proposal is also debated.