Donkeys and Mules
Animal Health

Why can't mules reproduce?

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Willy Quitzon
February 27, 2020 9:09PM

When a female horse and a male donkey mate, you get a mule, but two mules can’t mate to create another mule because of their chromosomal makeup.

A mule gets 32 horse chromosomes from its mother and 31 donkey chromosomes from its father. Mules are almost always sterile because those chromosomes don’t match up well enough to create egg or sperm cells.

I say “almost always” because there have been a few extremely rare instances of female mules reproducing with a male donkey or horse. But those are so rare they’re often called “miracles,” and there have been no documented instances of a male mule fathering any offspring. So, as far as we know, two mules cannot reproduce.

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Wiki User
June 21, 2010 7:15PM

The correct answer is beceayse a mule does not have a even number of chromosomes. They have 63 chromosomes.

A mule is the product of two different species (a horse and a donkey) mating with each other. Mules are always sterile because horses and donkeys have different chromosome numbers.

For the mule, having parents with different chromosome numbers isn't a problem. During mitotic cell division, each of the chromosomes copies itself and then distributes these two copies to the two daughter cells. In contrast, when the mule is producing sperm or egg cells during meiosis, each pair of chromosomes (one from Mom and one from Dad) need to pair up with each other. Since the mule doesn't have an even number of homologous pairs (his parents had different chromosome numbers), meiosis is disrupted and viable sperm and eggs are not formed.