MULE, HINNY, JENNY, Which IS WHICH?

What is a Mule?

A mule is a hybrid resulting from the mating of a donkey jack to a horse mare. The mule can be from any size and breed of donkey and horse. There are Miniature mules as small as 30", and Draft mules, from mammoth jacks and Belgian mares, over 18 hands. The smallest known mule is only 26" tall, and the largest mule in the world is 19.1 hands high! Mules come in both male and female, and have all of the right "plumbing". However, due to the way the donkey and horse chromosomes match up, the mule cannot reproduce. They are usually sterile, although a very few, very rare cases have been documented where female mules have been bred (by horses and donkeys) and have given birth to foals. No male mule, though, has ever been recorded to have sired a foal. Male mules should always be gelded, since they do not know they are sterile and think they are "working" stallions and act like it, too! Some mare mules are also spayed to help them with female problems.

What is a Hinny?

A hinny is the exact opposite cross as a mule. The father is a horse stallion, and the mother is a donkey jennet. Hinnies are also sterile, as are mules (the same one-in-a-million exception with female hinnies birthing applies). It is harder to get a hinny than a mule, since there are problems with the chromosomes matching up. The donkey has fewer gene pairs than a horse, and when the number is lower in the female (in this case, the donkey jennet) the conception rate drops. On the other hand, mules are very easy to breed, and mares that have had trouble conceiving a horse foal are often mated to a jack and have a mule foal with no problem!

A Hinny (front) is the product of breeding a donkey jennet to a stallion horse. This is an actual hinny and dam.

How can you tell the difference?

Between a mule and a hinny - really, you can't om 99% of the cases. Some say that a hinny is smaller and more horselike. Some say that the mule has more of the jack features. But really and truly, unless you know that the parents of a certain mule/hinny are a stallion and jennet or jack and mare, there is no rule to be able to tell at a glance. Hinnies may be smaller since most donkeys are smaller than horses, but some donkeys are 15 hands. Hybrids can grow taller than either one of the parents, too. Some think that hinnies have shorter ears than mules, but there is one mule in the ADMS books that has ears only one inch longer than his horse mother's. His full sister has regular long mule ears. This "ear theory"may stem from the fact that many hinnies are out of small jennets and pony stallions. Since many small ponies, especially Shetlands, tend to have small, rounded ears, the pony mule or hinny may have shorter ears in proportion to larger mules. One method that seems to be more reliable than others is to turn the mule or hinny out with a mixed group of equines. In theory, the mule will choose horses for company, as he was raised by a horse mare. The hinny is supposed to choose donkeys for company, from the donkey dam. We have seen a very few, rare hinnies that actually look like donkeys, and a few that look very much like horses with long ears. So hinnies seem to vary more greatly from one end of the spectrum to the other than do mules.

So, how do I tell the donkey from the mule or hinny?

You can tell 90% of donkeys from mules or hinnies by looking, but there are some donkeys that are mule-like, and some mules and hinnies that are very donkey like. The dark nose on donkeys with No Light Points confuses some people. Color, and size are not the best way to tell donkeys from hybrids. Neither is the length of the ears. The fastest way to tell is the tail. Donkeys have tails like a cow - long tailbone covered with short hair, and long switch on the very end. Mules and hinnies have tails like horses. Short tailbone, covered with longer hair all over. (Careful on animals with shaped/shaved tails - but the mule will still have a fuller tail with long hair higher up on the bone).

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