Mules are hybrid animals of the equine family that result from the mating of a donkey stallion (called a jack) with a horse mare. In genetic terms, this is classified as an F1 hybrid between Equus caballus X Equus asinus. Male mules are called mules or Johns, and are unable to reproduce. However, although they are genetically sterile, they are still affected by the same male hormones as any other stallion and they can become dangerous if not castrated. An uncastrated male mule cannot participate in shows and it is useless to keep them as a stallion. Since no male mule has ever sired a foal, you cannot mate two mules and expect offspring. In fact, there appears to be no authenticated instances of mules breeding among themselves even when the stallion has not been castrated. Interestingly, jack donkeys appear to be reluctant to mate with horse mares and many have to be trained to do so, though in these more modern times, artificial insemination can be attempted if all else fails.
In contrast, a fertile female mule (called a molly) can sometimes occur from this breeding combination. But this is so rare that the Romans had a saying, "cum mula peperit," meaning "when a mule foals" which is similar to saying "when hell freezes over." In some regions, a mule giving birth can trigger fear and superstition. When a mule produced a foal in Albania in 1994, it was thought to have unleashed the spawn of the devil on the small village; and when a mule in Morocco produced a foal in 2002, the locals feared it signaled the end of the world.
But it is true that a molly can be mated to either a horse or a donkey stallion; sometimes with very interesting results. It has been reported that a mare mule in Brazil has produced two 100% horse sons sired by a horse stallion. In the 1920s, when a molly at Texas A&M named "Old Beck" was bred to a horse stallion, she produced a horse son and when bred to a donkey, she produced mule offspring, including a mule daughter. And according to the American Donkey and Mule Society, there is an unverified case of a mare mule that produced a mule daughter. The daughter was also a fertile mule and produced a horse-like foal with some mule traits which was called a "hule". However, there are no reports as to whether the hule was fertile since it may have been castrated. It has also been reported that female hules may be fertile, but their offspring are usually feeble and die at birth. In another case, a molly gave birth to 2 foals in Nebraska in the mid-1980 and this was the first genetic testing of a mule's offspring. Tests showed no evidence that the mother had passed along any genetic markers from her donkey father, who was also the father of the foals. This is called "hemiclonal transmission". It is now known that in most fertile mule mares, they only pass on their maternal horse DNA.
However, even if sterile, mollies still have the female hormones coursing through their veins, which give them a strong maternal drive. They have been known to kidnap the foals of other equines sharing the same paddock.
The hinny is also a hybrid equine, but it is the result of the opposite mating: a horse stallion crossed with a donkey mare (called a jenny) but it is much less common. They are harder to produce because a stallion/jenny mating is less likely to result in pregnancy. This was once believed to be due to the donkey mare having a smaller womb, but the difficulty in impregnation suggests that it is largely a genetic issue. Donkeys (Equus asinus) have 62 chromosomes while horses (Equus caballus) have 64 chromosomes; infertile mules and hinnies have 63 chromosomes that are a mixture of one from each parent. The chromosomes have different structures and with the difference in number, too, this usually prevents the chromosomes from pairing up properly and creating successful embryos. In attempts among other species to create hybrids, the hybrid is much less likely to occur when the male has more chromosomes than the female, than when it is the other way around. It is almost like the female egg does not recognize sperm that has too many chromosomes, but does not seem to mind if the sperm has too few. Hinnies are also sterile, but a fertile female hinny in China is believed to be a unique case.
Hinnies and mules look slightly different from each other, yet for all practical purposes, hinnies, mollies and mules are classified and shown together under the general term of Mule.
The rarer hinnies are often said to be more horse-like than the mule, but more often it is difficult to tell them apart. The mule has a large head that is more donkey-like than horse-like, while the hinny has a smaller head that is more horse-like. The tail of the hinny is much more like that of the horse than is the tail of the mule. Generally, this is accounted for by the males of both species transmitting with greater power these parts of their structure. Hinnies are smaller and finer boned than mules, simply because of the fact that most donkeys are smaller than horses.
Mules come in every size and shape imaginable and all colors except overo (again due to genetics). Miniature mules under 36" can be seen all the way up to 17 hand Percheron draft mules (by Mammoth Jacks). The Poitou donkey was used exclusively for breeding huge draft mules from a breed of draft horse called the Mullasier - the Mule producer.
Mules' ears are usually somewhat smaller than a donkey's, but longer than the ears of the horse parent, and are roughly the same shape. Every mule will have a unique bray that is a combination of the horse's whinny and the grunting of the donkey's bray. And they show a natural resistance to disease and insects.
Mules are used in the same sports as horses; under saddle, in harness, for cutting, roping or dressage. They have more stamina and can carry more weight than a horse of equal size. This is due to what geneticists call "hybrid vigor". There is one aspect where the mule outshines the horse: high-jumping. Mules only 50 inches tall at the withers have been known to clear jumps of up to 72 inches. Amazingly, these jumps are from a standing start inside a marked area, not from a galloping approach.
Mules are not really stubborn, they simply will not put themselves in danger. A horse can be worked until it drops, but not a mule. That stubborn streak is the mule's way of telling humans that something is not right. It is not a good idea to abuse a mule, for they are clever and seem intelligent enough to plot revenge. However, treated kindly, they will do their best for their owner and with the utmost patience.
About Crystal Eikanger
Crystal Eikanger is a freelance writer, web designer, video editor and voice talent working as Ei-Kan Productions on www.rentacoder.com as well as other freelance sites. www.HorseClicks.com is a popular website filled with classifieds of horses for sale, horse trailers, tack, and horse related properties.
A professional portfolio of my multifaceted talents in the many fields I do freelance work-for-hire. I use many writing styles on a variety of subjects written for clients (or publish links to them); videos created for practice & for clients; audio samples of my natural human voice (never machine-generated!); links to websites created; logos, machinema, & other graphics. I would love to do your project! Contact me for details. Ei-Kan Productions stands for QUALITY...I can, so you can.
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Tuesday, October 20, 2009
The Myth of the Mysterious Mule and Molly
Monday, October 19, 2009
When Is A Horse Not A Horse? -- When It's A Donkey
A donkey is a long-eared equine that looks similar to a horse, shares the genus Equus with the horse, but is a completely different species.
Donkeys (Equus asinus) have 62 chromosomes while horses (Equus caballus) have 64 chromosomes. Crossing donkeys with horses results in hybrids called mules or hinnies, each of which ends up with 63 chromosomes. The male mules are always sterile, but on rare occasions, a fertile female can occur. The chromosomes between the two species have different structures and with the difference in number, too, this usually prevents the chromosomes from pairing up properly and creating successful embryos.
However, donkeys bred to donkeys always produce donkeys. You may hear many of the following terms: donkey, burro, ass, jackass, jennet, miniature donkey, mammoth, jackstock, standard, Mexican burro, and all of them are terms for donkeys. "Burro" is a colloquial term for the Spanish or feral type of donkey (wild burros). The term is used almost exclusively in the West and is correct only when referring to donkeys that are feral.
So where does the donkey come from, if not from a horse?
Well, after collecting and analyzing skin samples from donkeys in 52 countries in Europe, Asia, and Africa; and the dung from wild asses in Sudan, China, and Mongolia; scientists have concluded from mitochondrial DNA that African wild asses in Northeast Africa are the true ancestors of modern donkeys. These findings suggest that two populations of wild asses in Africa were the first to be domesticated about 6,000 years ago: the Nubian ass (Equus africanus africanus) and the Somali ass (Equus africanus somaliensis). Both of these wild asses are listed as critically endangered on the IUCN Red List. These two sub-species are thought to have had a role in the development of the modern donkeys that traveled with humans to other parts of the world.
The earliest domesticated donkey bones date to 4600-4000 BC, at El-Omari, a predynastic Maadi site in Upper Egypt near Cairo. Bones also have been discovered at sites in Syria, Iran and Iraq between 2800-2500 BC. In addition, donkey burials have been found at some sites which may reflect the value of a trusted domestic animal. Analysis of the skeletons revealed that they had been used as pack animals, judging by the signs of strain on their vertebrae. And the body morphology was midway between that of wild asses and modern donkeys, leading to the argument that the domestication process continued as a slow process over periods of several centuries. Interestingly, domestic donkeys are smaller than the wild ones, and in particular they have smaller feet.
The history of donkeys is tied to human history because when and where they were first used tends to mark the shift to more a mobile, trade-oriented society. But despite the critical role that it played in transportation throughout human history, the donkey is the least studied of all domesticated animals. Donkeys are desert-adapted and can carry heavy loads through arid lands allowing shepherds to move their households along with their herds. In addition, donkeys were ideal for the transport of food and trade goods throughout Africa and Asia.
Donkeys range in size from the Miniature Mediterranean that is less than 36 inches to the elegant Mammoth Jackstock that is 14 hands and up. The rare French Poitou donkey, which is characterized by a huge head and ears, and a very thick, shaggy, curled black coat, can stand 14 to 15 hand high. Unfortunately, there are estimated to be about 400 purebred Poitous left in the world today.
Donkeys in the USA are not grouped by "breed" but rather by type. The only exception to this is the Miniature Donkey. As of May 2008, they may now be recognized as a breed since they pass their unique breed traits on to their offspring consistently. The types of donkeys are labeled by their sizes; 36" and under are Miniature Mediterranean, 36.01-48" are Standard, 48.01" to 54" are Standard jennets or 56" for Large Standard, and 54/56" and over, Mammoth stock.
Donkeys differ from horses in conformation and the most noticeable difference is the ears. A donkey's ears are much longer in proportion to their width than a horse's. The necks are straighter than in horses, and most donkeys and all zebras lack a true wither. The croup and rump are also a different shape in the donkey since they lack the double-curve muscled haunch. Hoof shape varies as well; donkey hooves are rounder with more upright pasterns. The tail resembles a cow's; covered with short body hair and ending in a tassel of course hair. The coarse mane hair is stiffly upright, rarely laying over. Donkeys do not have a true forelock, although sometimes the mane grows long enough to comb down the face between the ears. Show donkeys wear their manes clipped short or shaved close to the neck.
Donkeys come in most of the same colors and patterns that horses do, but they look just a bit different. The colors of true pinto, horse aging gray, appaloosa, palomino and buckskin do not occur in the donkey or the mule or hinny. They also have a few unusual colors that are unique to the species such as dappled roan, blue-eyed ivory, frosted spotted and a unique spotting pattern called tyger spot that is similar to Appaloosa. Most donkeys have dark ear marks; dorsal stripes and shoulder crosses; as well as the light points of white muzzle and eye rings, and white belly and inner leg. Leg barring may be present as well. Occasional small dark spots at the throatlatch are called collar buttons and are good identifying markings. These typical donkey markings may be passed on in part or whole to mule or hinny offspring.
Donkeys can also perform all the gaits horses or mules do, and some are even gaited and can perform a single-foot gait.
Donkeys (geldings) can be wonderful guard animals for an entire herd of cattle, sheep or goats, or even a flock of chickens, geese or ducks. Their natural aversion to predators and inborn dislike of dogs will inspire the donkey to severely discourage any canine or coyote attacks on the herd. Dogs and donkeys usually don't mix, although they can be trained to leave the family dog alone. Only large Standard geldings, at least 3 years old, are recommended for guard duty. Miniatures are not suitable as guard donkeys.
Donkeys characteristically get by on less food than a horse of similar size, and need a lower protein content in their feed. Good grass hay and pasture is usually all a donkey needs.
Donkeys can be used just like horses under saddle and in harness, although donkeys are more laid back. . Donkeys are not really stubborn; they simply will not put themselves in danger. That stubborn streak is the donkey's way of telling humans that something is not right. It is not a good idea to abuse a donkey, for they are clever and seem intelligent enough to plot revenge. However, treated kindly, they will do their best for their owner and with the utmost patience, unless you are asking them to get their feet wet.
Otherwise, they are very friendly, and their versatile nature makes them excellent for children.
About Crystal Eikanger
Crystal Eikanger is a freelance writer, web designer, video editor and voice talent working as Ei-Kan Productions on www.rentacoder.com as well as other freelance sites. www.HorseClicks.com is a popular website filled with classifieds of horses for sale, horse trailers, tack, and horse related properties.