# How much inter-species breeding is possible? **URL:** \ **Category:** Factual Questions\ **Created:** [August 11, 2011, 11:03am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321 "2011-08-11T11:03:44Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![mac\_bolan00](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@mac\_bolan00](https://boards.straightdope.com/u/mac_bolan00)\ **Post date:** [August 11, 2011, 11:03am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/1 "2011-08-11T11:03:44Z")
i’m woefully lacking in knowledge in genetics. my understanding is that the result of an inter-species cross, a hybrid, is sterile. is this a rule? i read from somewhere that there was aready a successful mating between a tiglon/liger and a tiger (1/4 lion.) other questions: 1. how many different named species of animals are there that turn out to be just one species after all? 2. is there an ongoing effort to disprove my first premise, “all hybrids are sterile and cannot breed?” i get drowsy whenever i read darwin’s “origin” but i remember him repeating over and over that cross-species breeding is not an impossibility. there is just not experimentation and sufficient control to allow it. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [August 11, 2011, 11:23am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/2 "2011-08-11T11:23:44Z")
> [@mac\_bolan00](#): > > my understanding is that the result of an inter-species cross, a hybrid, is sterile. is this a rule? No, it’s just common. As I recall there are even lizard species that are composed of nothing but hybrids; the progenitor of such hybrid species being a female hybrid that as some lizards can was capable of parthenogenesis; breeding without a male. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [August 11, 2011, 11:41am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/3 "2011-08-11T11:41:25Z")
> [@mac\_bolan00](#): > > imy understanding is that the result of an inter-species cross, a hybrid, is sterile. is this a rule? No, it’s not even generally true. Most interspecies hybrids are fertile to some degree. At one end of the spectrum you get thing like wolf x coyote or cattle x banteng crosses that are 100% fertile. As you move down the line you get things like cattle x bison or cat x serval hybrids that are sometimes fertile then horse x donkey hybrids that are usually infertile and finally the few hybrids that, as far as we know, are always infertile. > [@](#): > > 1. how many different named species of animals are there that turn out to be just one species after all? The question doesn’t really make much sense. Species aren’t objectively real. They are just convenient labels that humans put on things. We define what makes a species base don arbitrary criteria and we and we get to change what makes a species. So by that standard no species at all turn out to be just one species. At some future date we may decide to re-assign some animals to another species, but then that will be the new definition of that species. They don’t turn out to be just one species, we just rearranged our arbitrary criteria. It’s impossible to know how many species might lumped together inn the future, but based on the trend of the last 20 years, we will end splitting far more species than we lump. Genetic evidence has turned up more species that turned out to be multiple species than it has apparent species that needed to be lumped. > [@](#): > > 1. is there an ongoing effort to disprove my first premise, “all hybrids are sterile and cannot breed?” There’s no need. > [@](#): > > i get drowsy whenever i read darwin’s “origin” but i remember him repeating over and over that cross-species breeding is not an impossibility. there is just not experimentation and sufficient control to allow it. “Origin of Species” contains [numerous examples](http://www.talkorigins.org/faqs/origin/chapter8.html) of well documented fertile hybrids. This wasn’t unknown 150 years ago. ---
**Author:** ![rhubarbarin](https://avatars.discourse-cdn.com/v4/letter/r/eb9ed0/32.png) [@rhubarbarin](https://boards.straightdope.com/u/rhubarbarin)\ **Post date:** [August 11, 2011, 11:43am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/4 "2011-08-11T11:43:54Z")
There are rather a lot of animal species where hybridization is possible, and while first-generation hybrids are indeed often sterile, many are fertile as well (especially mammals). Males are much more likely than females to be sterile. It’s more of a case-by-case basis. Often or always fertile first-generation hybrids off the top of my head: female Savannah cats (serval x domestic house cat) and ligers (lion x tiger), male and female beefalo (buffalo x domestic cow), male and female domestic dog x coyote and wolf and also coyote x wolf, and female wholphin (bottlenose dolphin x false killer whale). Most mules (and the vast majority of other horse hybrids) are famously infertile there have been plenty of verified cases of fertile female mules giving birth. There does seem to be ongoing study of all sorts of hybrids and attempts to breed them, but most often the domestic animals crosses, or naturally occurring hybrids taken from the wild. There are many genetically distinct sub-populations of animals that are considered one species, and sometimes the status of these sub-populations are changed to be considered separate species. And vice versa. Determining what makes a species a species isn’t the most exact science. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [August 11, 2011, 12:55pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/5 "2011-08-11T12:55:11Z")
And when you cross into the botanical side of things, there are inter_generic_ crosses (like [_Fatshedera lizei_](http://en.wikipedia.org/wiki/Fatshedera), a cross between [_Fatsia japonica_](http://en.wikipedia.org/wiki/Fatsia_japonica) and [_Hedera helix_](http://en.wikipedia.org/wiki/Hedera_helix)). _Fatshedera_ is commonly sterile, but has produced viable seed on occasion, so it’s one of the in-between cases. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [August 11, 2011, 1:09pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/6 "2011-08-11T13:09:47Z")
> [@jayjay](#): > > And when you cross into the botanical side of things, there are inter_generic_ crosses Several of the animal examples mentioned are also inter-generic: killer whale x dolphin, cattle x bison, cat x serval. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [August 11, 2011, 2:35pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/7 "2011-08-11T14:35:50Z")
> [@Blake](#): > > Several of the animal examples mentioned are also inter-generic: killer whale x dolphin, cattle x bison, cat x serval. :smack: I should have realized that… ---
**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:** [August 11, 2011, 5:42pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/8 "2011-08-11T17:42:36Z")
> [@](#): > > Species aren’t objectively real. They are just convenient labels that humans put on things. Or, as I like to put it, biology is messy. And malleable as the definition of “species” is, the definitions of any of the higher-level groupings are even more so. So there’s not really any significance to inter-generic crossings, because we could just as well have defined (say) cows and bison to be the same genus. In fact, I’ve heard it argued that an impartial observer (which we, of course, are not) would probably consider humans and chimps to be in the same genus. ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [August 11, 2011, 5:50pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/9 "2011-08-11T17:50:14Z")
[CatDog](http://en.wikipedia.org/wiki/CatDog) was infertile, but that episode never actually aired. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [August 11, 2011, 6:59pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/10 "2011-08-11T18:59:52Z")
> [@mac\_bolan00](#): > > 1. is there an ongoing effort… But there is an ongoing effort (for the last few centuries) to improve written communication by the use of Capitol Letters. On this board, we sort of expect that, along with reasonable grammar, spelling, etc. If you don’t want to do that, perhaps you would feel more at home on some other board – one where the kiddies post using leet-speak and other such silliness. But frankly, we’d like you to stay here. Your question was a serious one, with appropriate details, and written in understandable English. Such posters are welcome. Please consider staying. ---
**Author:** ![california\_jobcase](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)\ **Post date:** [August 11, 2011, 8:08pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/11 "2011-08-11T20:08:44Z")
How’s about proper spelling? (capital) ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [August 11, 2011, 8:19pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/12 "2011-08-11T20:19:02Z")
Capitol Letters is the name of the novel filled with steamy government correspondence I’m writing when I’m done with my current project on interspecies incest. ---
**Author:** ![TruCelt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/trucelt/32/523_2.png) [@TruCelt](https://boards.straightdope.com/u/TruCelt)\ **Post date:** [August 11, 2011, 8:31pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/13 "2011-08-11T20:31:24Z")
Big surprise in my aquarium once - a [Harlequin Rasbora](http://www.liveaquaria.com/product/prod_display.cfm?c=830+887+1065&pcatid=1065) bred with a [Purple Danio](http://www.thatpetplace.com/pet/prod/208558/product.web). Herman the frankenfish is doing just great after four years. I don’t intend to find out if he’s fertile, but he is certainly enamored of the [otto cats](http://www.thatpetplace.com/pet/prod/213338/product.web)that share his tank. :smack: Like many hybrids, he’s huge. 4 to 5 times bigger than his parents combined. ETA: [Purple Danio2](http://www.petsolutions.com/storefront/search.ep?keyWords=purple+danio) First link seems not to be working ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [August 11, 2011, 9:39pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/14 "2011-08-11T21:39:17Z")
> [@california\_jobcase](#): > > How’s about proper spelling? (capital) [Godwin’s law](http://en.wikipedia.org/wiki/Godwin%27s_law) at work! 🙂 ---
**Author:** ![Toucanna](https://avatars.discourse-cdn.com/v4/letter/t/3bc359/32.png) [@Toucanna](https://boards.straightdope.com/u/Toucanna)\ **Post date:** [August 11, 2011, 10:32pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/15 "2011-08-11T22:32:51Z")
> [@t-bonham@scc.net](#): > > [Godwin’s law](http://en.wikipedia.org/wiki/Godwin%27s_law) at work! 🙂 [nitpick nazi][Gaudere’s (Muprhy’s) law](http://en.wikipedia.org/wiki/Gaudere%27s_Law) at work![/nitpick nazi] 🙂 ---
**Author:** ![mac\_bolan00](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@mac\_bolan00](https://boards.straightdope.com/u/mac_bolan00)\ **Post date:** [August 11, 2011, 11:20pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/16 "2011-08-11T23:20:01Z")
> [@california\_jobcase](#): > > How’s about proper spelling? (capital) and apostrophes. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 12, 2011, 2:59am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/17 "2011-08-12T02:59:55Z")
> [@Toucanna](#): > > [nitpick nazi][Gaudere’s (Muprhy’s) law](http://en.wikipedia.org/wiki/Gaudere%27s_Law) at work![/nitpick nazi] 🙂 Muprhy’s? ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [August 12, 2011, 5:12am UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/18 "2011-08-12T05:12:04Z")
Greengrocers’ ---
**Author:** ![Wallydraigle](https://avatars.discourse-cdn.com/v4/letter/w/c0e974/32.png) [@Wallydraigle](https://boards.straightdope.com/u/Wallydraigle)\ **Post date:** [August 12, 2011, 4:47pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/19 "2011-08-12T16:47:33Z")
There are even a few inter-familial bird hybrids. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 12, 2011, 7:21pm UTC](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321/20 "2011-08-12T19:21:56Z")
> [@Wallydraigle](#): > > There are even a few inter-familial bird hybrids. There are some places where it’s common in humans, too. 😃 [Next page](https://boards.straightdope.com/t/how-much-inter-species-breeding-is-possible/592321.md?page=2)