Humans as Self-Domesticating Animals

at the end of the Pleistocene, certain human groups and their animal associates began progressively to show parallel reductions in size and stature, cranial gracilization, changes in post-cranial robusticity, shortening of the face and jaws, tooth crowding and malocclusion, and tooth-size reduction and simplification. There has been no recent attempt to explain the parallelism, although numerous explanations exist for the changes as they affect one or other of the parties. Some of the explanations are the same—such as response to Holocene warming, allometric and heterochronic effects, isolation of breeding units, reduction in activity levels, and diet quality—while others reflect the traditional division between the domesticated animal and the human driver. Thus for animals explanations may be couched as the effects of deliberate breeding, poor herd management, protection from predators, sensory deprivation, or culling. For humans the same morphological changes may be attributed to technological improvements, changing subsistence strategies, or greater intelligence. Very few post-1950 researchers apart from Zeuner have noted the parallels in these morphological trends, and none have commented on the differences in the explanations. Increasingly, however, selection pressures that did not involve intentional breeding are being proposed for animals, overlapping with those in the literature on human evolutionary change.

Restrictive environments, artificially constructed give us many of the traits shared with the animals we domesticate.