Episode 491: The Jumar

Further reading:

http://messybeast.com/genetics/hybrid-equines.htm

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

I stumbled across an interesting mystery animal recently and thought it would make a great topic for a Patreon episode. It’s supposed to be a hybrid animal, but as we’ll soon learn, it can’t possibly be what it’s said to be.

The animal is called a jumar or jumart, or sometimes a kumrah. The oldest record of a jumar dates to 1546 but there are many other accounts up to the beginning of the 20th century. The jumar is supposed to be the hybrid offspring of a horse and a cow, usually a bull and a mare. Sometimes it was supposed to be the offspring of a bull and a donkey mare.

Whatever its supposed origins, the jumar was said to look like a horse except for cow-like hindquarters and head, although with no horns. The hooves were usually solid like a horse’s hooves but occasionally cloven. A jumar was supposed to be stronger but smaller than an ordinary mule, which is a cross between a horse and a donkey.

There are plenty of reports of jumars, including individuals examined by naturalists, so it’s obviously a real animal. Could it really be a horse-cow hybrid? How closely related are horses and cows, anyway?

Not closely related AT ALL. The horse is almost as closely related to whales as it is to cows. They belong to totally different orders, and if you remember from the hybrids episode, it’s unusual for a hybrid to result from animals that share a genus, but extremely rare for animals that only share a family. Order is a step above family. There is literally no way that a horse and a cow could crossbreed successfully, but if somehow they did, the baby would not survive long enough to be born.

So the jumar can’t be a horse-cow hybrid, but at the same time, the jumar was a real animal. So what was it?

The first hint of a solution came from a French naturalist who lived in the 18th century. He wrote in 1771 about two dead jumars he bought and dissected. Both of them turned out to be ordinary mules. Specifically, they were hinnies, which are the offspring of a female donkey and a male horse. Most mules are offspring of a male donkey and a female horse.

Part of the reason that the hinny is a less common hybrid is because of the differences in chromosomes between horses and donkeys. Horses have 64 chromosomes, donkeys have 62. Mules and hinnies have 63 and are almost always sterile. In the case of a pair of animals with mismatched chromosomes, a baby is more likely to result when the father has the lower chromosome count, as is the case with the male donkey. A male horse has more chromosomes than a female donkey, so it’s less likely that a baby will result. Hinnies are almost always smaller than horses or mules because the mother donkey is a smaller animal than the mother horse.