Advantages of Mules

“The advantages of mules have been known since ancient times. Fully grown mules tend to have the height and musculature of their mother, while inheriting the leaner physique and more nimble legs of their jack father. This produces a hybrid with the strength, but nowhere near the weight, of the mother. The two most common draft-mule crosses today are mammoth jacks bred to black or gray Percheron mares, and the sorrel and dun mules produced by mating with Belgian mares. When mature, the hybrid offspring weigh as much as seven hundred pounds less than their mother, giving the finished mule an extraordinary strength-to-weight ratio and agility far beyond its roots in the horse. In the equine world, the most common adjective applied to mules is ‘athletic.’

The hybridization of closely related but not exactly matched species, like horses and donkeys, produces sterile offspring, and mules cannot reproduce themselves. (Donkeys have sixty-two chromosomes; horses have sixty-four. This creates a mule with sixty-three chromosomes, preventing a full “chain” of matches that can produce an embryo.) But the contributions from the more feral side of the donkey sire more than make up for the mule’s inability to reproduce itself. Mules endure heat much better than horses and can travel long distances without water. They require about half the feed of horses and don’t gorge on grain. The legs and hooves of a mule are stronger and tend not to ‘founder,’ or go lame, on rocky ground or with hard use. Mules live and continue to work until they are thirty years old, while most horses have finished their working lives at twenty. Another critical advantage is contributed by the donkey’s large eyes. Because mules’ eyes are set farther back on the head and are more D-shaped than a horse’s, their peripheral vision includes their hind feet, making them exceptionally sure-footed and confident in rough terrain.”