Horses, donkeys, and mules are similar, related animals. The biggest differences are in the number of chromosomes. Horses have 64 chromosomes, while donkeys have 62. When they mate, they produce mules or hinnies, which have 63 chromosomes. A mule is the offspring of a mare (female horse) and a jack, or male donkey. The offspring from male horses (stallions) and female donkeys (jinnets) are called hinnies. Most people just lump jinnies and mules together and refer to them as mules, which is what we will do here.
Mules are hybrids, each having one donkey and one horse parent. They can be male or female, but cannot reproduce because of the odd number of chromosomes. Very rarely (like 1 in a million), female donkeys have given birth, but no male mule has ever been known to sire one.. Male mules actually need to be gelded or castrated so they are more sociable, mild mannered, and safer for their handlers.
Other names for mules and hinnies are Johns or Jacks (male) and mollies or jennies (female). Have you ever heard of the term "longears?" It is an endearing term for donkeys and mules. Horses have small ears, while donkeys and mules have long ears. Mule ears are not as long as donkeys and a hinnys ears are shorter and much wider than donkey ears.
The tails of horses, donkeys, and mules are different as well. Donkey tails are similar to cow tails, with a tuft of hair on the end. They are also not as long as the tails of horses and mules. Tails of horses and mules have long thin hair that goes all the way to the end.
When a horse is scared or "spooked", it will run, but a donkey will either stand and defend its ground or simply freeze. So what does a mule do? It will do either, as it is part horse and part donkey!
Donkeys and mules are considered to be more intelligent than horses. When they freeze, it is part of their "well-developed instinct for self-preservation". Although often considered to be stubborn, most experts think that they are just thinking the situation over and are not likely to place themselves in danger. Horses will allow themselves to be worked to exhaustion, while mules won't.
Mules, as with most hybrids, were bred to join together the most desirable qualities from donkeys and horses. They get their strength and stamina from the horse while their patience, sure-footed gait, and intelligence comes from the donkey.
There are 185 breeds of donkeys, with about 41 million in the world today. China has the most, with about 11 million. George Washington is considered to be "Father of the American Mule. In 1785 he was gifted a large Spanish Jack from King Carlos III of Spain. The next year-1786-he received a Maltese jack and two jennets from ZFrench General Lafayette. He had his prize mares bred to the new jacks and became the first mule breeder in America.