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 lambei Furthermore, evidence from "E. lambei" mtDNA now proves that modern horses are not so far removed from their ancient ancestors. Many scientists believe that a good argument can be made that "E. caballus", too, should receive protection as a form of native wildlife in North America. However, this topic is still highly debated by wild horse management agencies. This debate has significant implications to wildlife management in North America, including protection and conservation for modern species. Equus lambei Equus lambei (common names include Yukon horse, and Yukon wild horse) is an extinct species of the genus "Equus". "Equus lambei" ranged