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
Ticks of domestic animals classification of the Acari, including the two families of ticks of importance to domestic animals is in the article Mites of livestock. "Amblyomma" species are widespread on domestic animals throughout tropical and subtropical regions. Typical "Amblyomma" species are: "Amblyomma americanum", the lone star tick of southern and eastern USA; "Am. cajennense", the Cayenne tick of South America and southern USA; "Amblyomma variegatum", the bont tick of Africa and the Caribbean (see Gallery below for photograph of female and male). A typical "Rhipicephalus" species is "Rhipicephalus sanguineus", the tropical dog tick, specialized to feed only on dogs. It is distributed globally