Donkey of Asiatic wild ass or onager, "Equus hemionus", and three subspecies of the kiang, "Equus kiang", of the Himalayan upland. A male donkey (jack) can be crossed with a female horse to produce a mule. A male horse can be crossed with a female donkey to produce a hinny. Horse-donkey hybrids are almost always sterile because horses have 64 chromosomes whereas donkeys have 62, producing offspring with 63 chromosomes. Mules are much more common than hinnies. This is believed to be caused by two factors, the first being proven in cat hybrids, that when the chromosome count of the male
Female cosmetic coalitions will be whether Male B gains sufficient fitness via a roving strategy of picking up cycling, non-cosmetic females. If Male A is not able to compete with Male B in terms of dominance, he is better off choosing the cosmetic females. Because Female B and her non-cosmetic female neighbors get the attentions, but no reliable investment, from Male B, they discourage any investment from the likes of Male A. Once costs of encephalization begin to bite and cooperative strategies are needed to support offspring, how many females will be choosing philanderers in preference to investors? Those females are not likely