Donkeys and Mules have a slightly longer average pregnancy length than that of a horse - at 12 months or 365 days.
The normal GL reference for mule pregnancies was 316.9–365.3 days. Therefore, GL of equine pregnancies was longer than of mule pregnancies. Gestational length was not different when pregnancies resulted in females or males within each group.
A female horse and a male donkey have a mule. But hinnies and mules can't have babies of their own. They are sterile because they can't make sperm or eggs.
The average length of pregnancy in the mare is 338 to 343 days. However, normal gestation can range from 320 to 380 days. You needn't become overly concerned if your mare is past due.
In short, a mare's pregnancy length is like 10-12 months(326-354 days).
How long is a horse pregnant? Well, the short answer is 10 to 12 months, or from approximately 326 days to 354 days (although there have been cases where gestation for a mare has gone as long as 365 to 370 days).
Elephants are the largest land mammals in the world, so it's perhaps not surprising that they have the longest pregnancy of any living mammal: African elephants are pregnant for an average of 22 months, whilst for Asian elephants it's 18 to 22 months.
Generally, assuming a filly is healthy and on a good plan of nutrition, she can be bred as early as two years of age, although many breeders suggest waiting until three years of age. Mares can continue to produce foals well into their late teens or early to mid 20's.
Mares: Can have 0 to 20, with an average broodmare producing around 15 to 20 foals in her life. Stallions: Most stallions are bred 30 to 50 times a year. If 40 of those attempts result in a live foal, a stallion could have 600 foals in his life.
But while mules have turned out to be extremely valuable work animals, neither mules nor hinnies can mate among themselves to produce their own offspring because of their odd origins.
Mules can live up to 50 years, with an average lifespan of 30-40 years.
Mules can be either male or female, but, because of the odd number of chromosomes, they can't reproduce. However, a male mule should be gelded in order to make him a safe and sociable animal. Except for the long ears, mules look very similar to horses, but their muscle composition is different.
Fertility. A mule has 63 chromosomes, intermediate between the 64 of the horse and the 62 of the donkey. Mules are usually infertile for this reason. Pregnancy is rare, but can occasionally occur naturally, as well as through embryo transfer.
It is not uncommon for female mules to come into estrus and for male mules to display signs of teasing other female equine when in estrus. Most mule owners will castrate male mules, and some will even spay female mules (remove the ovaries) in hopes of changing behavior associated with estrus or aggression.
Those mismatched chromosomes make it hard to make viable sperm and eggs. So mules are sterile because horse and donkey chromosomes are just too different.
Mature stallions can breed two or three mares a day throughout a long breeding season and maintain a good level of fertility, but young stallions should not be expected to handle this level of work.
Stallions may always be “on,” but that doesn't mean they can constantly breed. After all, they do need time to eat, sleep, exercise, and socialize. A stallion can typically cover one to three mares a day and about 30 to 40 mares in one year.
Registered stallions and mares can breed with minimal human intervention, through natural cover in the pasture. Pasture breeding continues as an accepted breeding method recognized by many breed registries. As in the wild, a stallion roams with a band of mares.
Elephants. Elephants have the longest gestation period of all mammals, carrying their young for 18 to 22 months before giving birth. Long developmental periods are common among highly intelligent animals.
The moment a male hippocampus whitei, also known as a White's Seahorse, gave birth to around 100 offspring has been caught on camera at Sea Life Sydney Aquarium. The babies of this endangered species, similar in size to a grain of rice, emerged from their father's pouch.
Well camouflaged as they cling to stalks of seagrass in their shallow habitats, seahorses can be hard to see. Their truly remarkable biological claim to fame, however, is that male seahorses and sea dragons get pregnant and bear young—a unique adaptation in the animal kingdom.
The most likely reason that mares lie down after mating is because they are overwhelmed and need to rest to bring their heart rate back down to normal levels. Stallions can be aggressive and hyperactive when courting and mating, and horses are socially sensitive creatures.
In horses, twin fetuses are uncommon. Carrying them to term is even more unusual, and birthing healthy twin foals is especially unlikely. “Twin pregnancies are extremely undesirable in horses, as they almost always have a bad outcome,” said Dr.
Mares have a twin pregnancy rate of between 3 and 30% depending on the breed of the horse. A commonly accepted rate in Thoroughbred mares in Australia is 10 – 15%. Mares that are allowed to carry twin pregnancies are likely to suffer complications as a result.