Chromosomes: Horses have 64 chromosomes and donkeys have 62. Mules are in the middle, with 63 chromosomes. Fertility: Unfortunately, having 63 chromosomes isn’t great for fertility.

Corolla wild horse ‘Flint’ laid to rest beside his son in North Carolina’s Outer Banks Raymond Jr. the mule was believed to be in his late 20s and an offspring of a wild Banker mare and a ...