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
Equus publicus a property value of more than 100,000 denarii or else inheritance, but the equus publicus was only attainable by way of inheritance from a father. In imperial times, after the reforms of Augustus, the status could be granted by an emperor, along with inheritance from a father. Equus publicus The Equus publicus (literally "horse bought by the commonwealth") was an honourable status in ancient Rome, granting its holder a military horse paid for by the state, along with the cost of its fodder for its whole life. The money for the horse was called "aes equestre", whilst the annual money