Reproductive isolation from a cross between a horse and a donkey or between a mare and a donkey, respectively. These animals are nearly always sterile due to the difference in the number of chromosomes between the two parent species. Both horses and donkeys belong to the genus "Equus", but "Equus caballus" has 64 chromosomes, while "Equus asinus" only has 62. A cross will produce offspring (mule or hinny) with 63 chromosomes, that will not form pairs, which means that they do not divide in a balanced manner during meiosis. In the wild, the horses and donkeys ignore each other and do not
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