The hybrid offspring of a male horse and a female donkey is called a hinny. A hinny is the reciprocal cross of a mule: its father is a stallion, while its mother is a jenny, or female donkey.
Hinnies and mules are both equine hybrids, but hinnies are generally less common. They can differ from mules in body shape, size, temperament, and physical characteristics. A hinny often has a lighter head, shorter ears, and a tail resembling that of its donkey mother.
The distinction is easy to mix up because both hybrids come from horses and donkeys. A male donkey bred with a female horse produces a mule; a male horse bred with a female donkey produces a hinny. The parent combination, not simply the animal’s appearance, determines the name.
Like most horse-donkey hybrids, hinnies are usually sterile. Their parents have different chromosome numbers, which creates difficulties during the formation of reproductive cells. This sterility is one reason hinnies and mules are not considered separate breeding populations.