Horses and donkeys both belong to the Equus genus of the Equidae family, but genetically, these species have a different number of chromosomes. Donkeys have 62 chromosomes, and horses have 64. Although donkeys and horses are capable of breeding, their genetic inconsistencies result in hybrid offspring that cannot reproduce due to an uneven number of chromosomes, according to Pawnation.
Donkeys and horses share the basic physical qualities of the Equidae family: a long muzzle, pointed ears, hooved feet and a four-legged body. However, horses typically have loose, flowing manes and tails, while donkeys have a short, spiky mane. Donkey tails are often slender and shaggy with a short tuft of hair at the end. In terms of facial proportions, horses have longer muzzles and shorter ears than donkeys. Mules are the product of breeding a male horse with a female donkey, and a hinny is the opposite form of hybrid.
Both beasts of burden are exceptionally strong and able to carry heavy loads, but horses are superior in speed. The fastest breeds can complete a one-mile run in roughly 93 seconds, according to HowStuffWorks. Horses protect themselves by living in hierarchical herds, making them easier for humans to subdue. Donkeys have a reputation for being stubborn and are more likely to stand their ground while assessing potential threats.