What do you get when you cross a horse with a donkey? You get a mule. Although mules and donkeys share many characteristics, they have differences that make each animal unique. A key difference is that a mule is part horse while a donkey is simply all donkey.
Like the horse, a donkey is a specific breed of animal. Breeding a donkey to a donkey produces a donkey. The American Donkey and Mule Society describes the donkey as ranging in size from miniature to the Mammoth Jackstock. Miniature donkeys are under 36 inches while the Mammoth Jackstock stands over 14 hands. The standard donkey ranges from 48.01 inches to 54 inches.
One of the most noticeable features of the donkey is its ears. Along with its elongated ears, donkeys also have a straighter neck and back than horses. The straighter back is attributed to the true wither that most donkeys lack. This is also a feature seen in one of the donkey's close relatives, the zebra.
Reproduction is a key difference between donkeys and horses. Rural Heritage explains that the gestation period for a donkey ranges from 11 to 14 months but generally lasts 12 months. A horse's gestation is roughly 11 months. While producing twins is rare in both donkeys and horses, it is more likely to occur with donkeys. Due to the chromosome difference between donkeys and horses (62 for donkeys and 64 for horses), breeding the two together nearly always produces a sterile offspring-the mule which is born with 63 total chromosomes.
Unlike the horse and donkey, a mule is not a specific breed but rather a hybrid species. A mule is created by breeding a donkey with a horse. The common conception that mules are unable to reproduce is mostly accurate. Rural Heritage explains that in rare instances, a mare mule will be fertile. The American Donkey and Mule Society substantiates the sterility of mules saying "very few (about 1 in 1 million) mare mules have had foals."
Within the mule family are the mule and hinnie. More often than not, people refer to all mules as "mules." A mule is created when a donkey stallion is bred to a horse mare. The hinnie is a mule that is created from a stallion horse and a female donkey, also known as a jennet. A mule or hinnie can be either male or female.
The physical characteristics of mules are similar to the donkey. The American Mule and Donkey Society describe the mule as having smaller ears than the donkey and shaped like that of its horse parent. It takes its body conformation from both parents. Miniature mules are less than 36 inches but due to their horse lineage, full size mules can reach an impressive 17 hands high.
Differences between mules and donkeys
There are some basic differences between mules and donkeys. Along with the sterility and ear size, mules make a different sound from donkeys. The classic call that the donkey is known for is not a trait of mules. Instead, mules have a combination call of the horse and donkey which is usually unique with each mule.
A unique trait of donkeys is its spinal column. According to Rural Heritage, horses have the fifth lumbar vertebrae, a feature that donkeys lack. Mules typically inherit the fifth lumbar vertebrae from their horse parent. Because they have one horse parent, mules are also generally larger than donkeys.