Donkey the environment. They may compete with livestock and native animals for resources, spread weeds and diseases, foul or damage watering holes and cause erosion. Few species of ass exist in the wild. The African wild ass, "Equus africanus", has two subspecies, the Somali wild ass, "Equus africanus somaliensis", and the Nubian wild ass, "Equus africanus africanus", the principal ancestor of the domestic donkey. Both are critically endangered. Extinct species include the European ass, "Equus hydruntinus", which became extinct during the Neolithic, and the North African wild ass, "Equus africanus atlanticus", which became extinct in Roman times. There are five subspecies
Proconsul africanus has a talus in which the trochlear surface is highly curved and deeply grooved. The foot of this species possessed a transverse arch. "Proconsul africanus" had a brachial index of 96 which is comparable to the extant genus "Pan". Overall the skeleton of this species can be described as being robust. This species had an average body mass of around . Based upon the dental morphology, it is conjectured that "Proconsul africanus" was a frugivorous species. A study by Aiello in 1981 concluded it was a "below-branch feeder." Based on postcranial pieces, "Proconsul africanus" was likely an arboreal quadruped. Proconsul