Origin of the domestic dog as the Tibetan people. A population genetic analysis then showed a significant convergence between humans and dogs in Tibet. Like the Tibetan people, Tibetan mastiffs appear to have derived these benefits partially from the EPAS1 gene, acquired through introgression. In 2015, a study found that when dogs and their owners interact, extended eye contact (mutual gaze) increases oxytocin levels in both the dog and its owner. As oxytocin is known for its role in maternal bonding, it is considered likely that this effect has supported the coevolution of human-dog bonding. One observer has stated, "The dog could have arisen only
Dog anatomy allowed dogs (including both domestic dogs and their wild prehistoric ancestors) to survive in the harsh Arctic environment and other cold areas of northern Eurasia and North America, which are both very dry and very cold. Dog anatomy Dog anatomy comprises the anatomical studies of the visible parts of the body of a canine. Details of structures vary tremendously from breed to breed, more than in any other animal species, wild or domesticated, as dogs are highly variable in height and weight. The smallest known adult dog was a Yorkshire Terrier that stood only at the shoulder, in length along