# Do mules reproduce? **URL:** \ **Category:** Factual Questions\ **Created:** [March 28, 2009, 10:04am UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078 "2009-03-28T10:04:48Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![NineToTheSky](https://avatars.discourse-cdn.com/v4/letter/n/b5a626/32.png) [@NineToTheSky](https://boards.straightdope.com/u/NineToTheSky)\ **Post date:** [March 28, 2009, 10:04am UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/1 "2009-03-28T10:04:48Z")
I have been reading a review of a book: [13 Things That Don’t Make Sense: The Most Intriguing Scientific Mysteries Of Our Time by Michael Brooks](http://www.amazon.co.uk/exec/obidos/ASIN/1861978170/ref=ord_cart_shr?_encoding=UTF8&m=A3P5ROKL5A1OLE). It sounds interesting, and perhaps the answers to the following question will be revealed when I have the book; but in the meantime, can anyone explain this: The review says: ‘Brooks asks the question: what is life? Again, scientists don’t know. There are inanimate objects. And then there living things. But no scientist on earth can tell you where the fundamental difference between thses two states lies. One definition might be that living things reproduce themselves. But then, so do some non living things, such as computer viruses.\*\* And some living things, such as mules, do not\*\*.’ Is that correct: mules don’t reproduce? ---
**Author:** ![madmonk28](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madmonk28/32/20811_2.png) [@madmonk28](https://boards.straightdope.com/u/madmonk28)\ **Post date:** [March 28, 2009, 10:19am UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/2 "2009-03-28T10:19:20Z")
Mules are the product of a mating between a horse and a donkey. Here is a Wikipedia article: > **[Mule](https://en.wikipedia.org/wiki/Mule)** > > The mule is a domestic equine hybrid between a donkey and a horse. It is the offspring of a male donkey (a jack) and a female horse (a mare). The horse and the donkey are different species, with different numbers of chromosomes; of the two possible first-generation hybrids between them, the mule is easier to obtain and more common than the hinny, which is the offspring of a female donkey (a jenny) and a male horse (a stallion). > Mules vary widely in size, and may be of any color. They are mor... ---
**Author:** ![Westrogothia](https://avatars.discourse-cdn.com/v4/letter/w/3ab097/32.png) [@Westrogothia](https://boards.straightdope.com/u/Westrogothia)\ **Post date:** [March 28, 2009, 10:21am UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/3 "2009-03-28T10:21:56Z")
mules are the offspring from a cross species mating (male donkeys and female horses) since the two diffrent species have diffrent numbers of cromosomes the offspring is infertile (most of them) so no they cant breed. … too slow ---
**Author:** ![Argent\_Towers](https://avatars.discourse-cdn.com/v4/letter/a/e8c25b/32.png) [@Argent\_Towers](https://boards.straightdope.com/u/Argent_Towers)\ **Post date:** [March 28, 2009, 10:38am UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/4 "2009-03-28T10:38:11Z")
The sterile offspring of a horse and a donkey…There’s no room in the new world for a bastard like that! ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [March 28, 2009, 12:19pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/5 "2009-03-28T12:19:59Z")
Apparently, _some_ female mules are capable of reproduction, but no male mules are. I remember hearing about at least one instance a few years ago. It’s rare, but it can happen. ---
**Author:** ![ivylass](https://avatars.discourse-cdn.com/v4/letter/i/9de053/32.png) [@ivylass](https://boards.straightdope.com/u/ivylass)\ **Post date:** [March 28, 2009, 1:15pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/6 "2009-03-28T13:15:32Z")
I think ligers (lion/tiger crossbreeds) are also sterile. ---
**Author:** ![cwthree](https://avatars.discourse-cdn.com/v4/letter/c/9de0a6/32.png) [@cwthree](https://boards.straightdope.com/u/cwthree)\ **Post date:** [March 28, 2009, 5:07pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/7 "2009-03-28T17:07:02Z")
> [@NineToTheSky](#): > > …There are inanimate objects. And then there living things. But no scientist on earth can tell you where the fundamental difference between thses two states lies. One definition might be that living things reproduce themselves. But then, so do some non living things, such as computer viruses.\*\* And some living things, such as mules, do not\*\*.’ Is that correct: mules don’t reproduce? Mules have fully functional reproductive organs, but (generally) the sperm and eggs they produce are not capable uniting with each other to create a viable embryo. A female mule has ovaries which produce mature egg cells and a uterus which can sustain a pregnancy (via embryo transfer or the exceedingly rare natural pregnancy), and experiences heat cycles. A male mule has testicles which produce sperm and testosterone, and should be gelded to avoid unwanted stallion behavior. To the best of my knowledge, a male mule cannot impregnate a female mule, a female donkey, or a female horse; the few cases of pregnant female mules result from mating with a male horse or donkey. “Living things reproduce themselves” is a poor definition at best. Many thing that are clearly alive, such as mules and domestic banana plants, can’t reproduce in the sense that they’re (functionally) infertile. The dichotomy between “inanimate objects” and “living things” seems odd as well. There’s no reason you couldn’t have a life form that doesn’t move, or even reproduce, but which is nevertheless alive in the sense that it metabolizes nutrients that it acquires from its environment. ---
**Author:** ![The\_Second\_Stone](https://avatars.discourse-cdn.com/v4/letter/t/bbe5ce/32.png) [@The\_Second\_Stone](https://boards.straightdope.com/u/The_Second_Stone)\ **Post date:** [March 28, 2009, 5:13pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/8 "2009-03-28T17:13:44Z")
The word mule has a connotation of sterile in and of itself. There are very rare instances of mules giving birth, but it happens less than one incident in a century. Horses and donkeys have different numbers of chromosomes, causing sterility. A boy mule is a jackass. A girl mule is a jenny. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [March 28, 2009, 5:21pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/9 "2009-03-28T17:21:09Z")
> [@The\_Second\_Stone](#): > > A girl mule is a jenny. Unless she actually does give birth, then she’s a “molly”. ---
**Author:** ![cwthree](https://avatars.discourse-cdn.com/v4/letter/c/9de0a6/32.png) [@cwthree](https://boards.straightdope.com/u/cwthree)\ **Post date:** [March 28, 2009, 5:26pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/10 "2009-03-28T17:26:33Z")
> [@The\_Second\_Stone](#): > > A boy mule is a jackass. A girl mule is a jenny. A jackass is a male donkey (also called a _jack_ or _donkey jack_). A male mule is a _john mule_ or a _jack mule_. Some people use “john mule” to refer only to a male mule who has been gelded. A jenny is a female donkey. As **broomstick** pointed out, a female mule is a _molly_ or _molly mule_. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [March 28, 2009, 5:31pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/11 "2009-03-28T17:31:06Z")
> [@The\_Second\_Stone](#): > > A boy mule is a jackass. A girl mule is a jenny. A male mule is often called a jack, if you happen to holding a conversation with someone intimately involved with mules. But the term ‘jackass’ means a male ass, i.e., a male animal of the donkey or burro species (Equus hemionus, IIRC). Connotatively, a jack or jenny ass usually refers to the full-size horse-sized animal, formerly a draft animal but now (IIRC) usually kept only for mule production, while burro and usually donkey refer to the pony-sized non-draft breeds within that species. ---
**Author:** ![capybara](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/capybara/32/202_2.png) [@capybara](https://boards.straightdope.com/u/capybara)\ **Post date:** [March 28, 2009, 6:02pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/12 "2009-03-28T18:02:55Z")
Ok, why would you geld a mule, then? If gelding more meant as a behavioural function rather than reproductive? ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [March 28, 2009, 6:16pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/13 "2009-03-28T18:16:36Z")
> [@capybara](#): > > Ok, why would you geld a mule, then? If gelding more meant as a behavioural function rather than reproductive? Right. Ungelded mules, like ungelded horses and donkeys, tend to be aggressive. Gelding makes them a lot more docile and biddable. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 28, 2009, 7:02pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/14 "2009-03-28T19:02:47Z")
Of course, even though mules (and bananas) can’t reproduce, they’re composed of things that can and do. Mule cells can divide just like any other cell, or they wouldn’t be able to grow or heal wounds. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 28, 2009, 7:12pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/15 "2009-03-28T19:12:34Z")
> [@cwthree](#): > > “Living things reproduce themselves” is a poor definition at best. Many thing that are clearly alive, such as mules and domestic banana plants, can’t reproduce in the sense that they’re (functionally) infertile. This also includes worker ants and honeybees. ---
**Author:** ![NineToTheSky](https://avatars.discourse-cdn.com/v4/letter/n/b5a626/32.png) [@NineToTheSky](https://boards.straightdope.com/u/NineToTheSky)\ **Post date:** [March 28, 2009, 7:13pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/16 "2009-03-28T19:13:14Z")
So, are mules the only mammals that are (usually) infertile? ---
**Author:** ![The\_Second\_Stone](https://avatars.discourse-cdn.com/v4/letter/t/bbe5ce/32.png) [@The\_Second\_Stone](https://boards.straightdope.com/u/The_Second_Stone)\ **Post date:** [March 28, 2009, 7:56pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/17 "2009-03-28T19:56:15Z")
I’m an idiot. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [March 28, 2009, 8:26pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/18 "2009-03-28T20:26:30Z")
> [@NineToTheSky](#): > > So, are mules the only mammals that are (usually) infertile? No. It’s the most common ‘mule’ (in the metaphorical usage) cross, hence the use of the name to describe such crosses. Interspecies crosses within a mammal genus _usually_ but not always are infertile. (My layman’s guess is that interspecies crosses in birds among other classes tend to be fertile more commonly.) Dog-wolf and dog-coyote crosses are fairly common and fertile. (Speaking of carnivore interspecies crosses, the common name for one species derives from a mistaken belief it was a cross: Panthera leo is the lion, panthera pardus is what was in Shakespeare’s time the pard, hence the trivial name. But it was believed by 17th century biologists that the typical P. pardus was a cross between the leo and the pard, hence it was called the leopard.) ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 28, 2009, 8:26pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/19 "2009-03-28T20:26:46Z")
> [@NineToTheSky](#): > > So, are mules the only mammals that are (usually) infertile? No. Many other interspecific hybrids are sterile, such the liger and tigon, crosses between lion and tiger (although as in mules females are sometimes fertile), donkey-zebra crossses, etc. In the [naked mole-rat](http://en.wikipedia.org/wiki/Naked_mole_rat) only one female in a colony breeds, the others being functionally sterile and serving as “workers” as in ant colonies. However, this condition is temporary due to hormonal suppression by the “queen”; the workers are genetically capable of breeding if a queen is not present. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [March 28, 2009, 9:30pm UTC](https://boards.straightdope.com/t/do-mules-reproduce/491078/20 "2009-03-28T21:30:42Z")
> [@The\_Second\_Stone](#): > > I’m an idiot. That shouldn’t prevent you from breeding, however. 😃 [Next page](https://boards.straightdope.com/t/do-mules-reproduce/491078.md?page=2)