tions and ligers and birdfish, oh my!

September 10, 2005 1:35 PM

Can/do fish species and bird species interbreed? Not fish-and-bird together, just to be clear. I'm not insane, thanks very much. :)

I know that horses and donkeys can create mules. I know that lions and tigers can create tions and ligers (bred for their skills in magic, you know). What other examples of this sort are there, and are there any examples of fishes or birds doing this?

posted by Kickstart70 to Science & Nature (18 answers total)

Wow, you should change that "and" to an "or" because I had to read this question several times before I figured out it wasn't a chicken of the sea joke.
posted by 517 at 1:52 PM on September 10, 2005

Best answer: On the basis of "What other examples of this sort are there", since the following isn't about birds or fish:

Most North American lampropeltine snakes can interbreed; despite the fact that they're from different genera, their offspring are fertile: specifically, corn and rat snakes (Elaphe or Pantherophis, depending on the authority), bullsnakes, gopher and pine snakes (Pituophis), and kingsnakes and milk snakes (Lampropeltis).

They turn up in the pet trade more regularly than I'd like (see below): I've personally seen jungle corns (California kingsnake x corn snake), Baird's rat snake x corn snake, and even a Sinaloan milk snake/Florida kingsnake cross (which is kind of amazing considering that the kingsnake is seriously ophiophageous and quite a bit larger than the other one), and know about gopher/corn and rat/corn snake crosses as well. There are, no doubt, others; presumably every species in Tribe Lampropeltini/Subfamily Lampropeltinae (again, depending on the authority) is capable of doing this.

I have no idea why this works, or how the offspring can be fertile. Getting it to even happen involves a bit of trickery: getting the male snake all hot and bothered with a female of the same species, then switching the female at the last minute before intromission (a technical term for "fucking") occurs. In the wild, it happens very, very rarely.

(As an aside, this is spooking some snake breeders who worry that the captive-breeding gene pool will get polluted by some twit who doesn't understand the difference between dog breed and species, and thinks all the above is just neato cool.)
posted by mcwetboy at 1:55 PM on September 10, 2005

Response by poster: Thanks mcwetboy, I should have also included reptiles. And insects, I guess.
posted by Kickstart70 at 2:13 PM on September 10, 2005

Certain species of freshwater fish can interbreed, for example, swordtails and guppies. (Some fish stores will have these.) There's quite a variety amongst fish species in how they breed, so at a minimum I would guess that both fish would have to breed the same way (laying a nest of eggs, or carrying the fertilized eggs around in their mouths, or livebearers). Obviously, the fish would also need to have the same kinds of water conditions to be in the same place at the same time, so you couldn't cross salt and freshwater, so no bluefin tuna + rainbow trout mashups, unless a laboratory were involved, and even then I'm not sure it would work.
posted by ambrosia at 2:53 PM on September 10, 2005

I should add that while the swordtail + guppy mix happens in captivity, I'm not sure that this would happen in the wild.
posted by ambrosia at 2:54 PM on September 10, 2005

Pacific salmon species interbreed routinely, especially pinks and chums, and chums and sockeyes. Apparently escaped Atlantic farmed fish are also starting to cross breed with native Pacific species, with the potential for disastrous consequences for fisheries.
posted by McGuillicuddy at 3:01 PM on September 10, 2005

On the bird side of things, Baltimore Orioles and Bullock's Orioles are well-known to interbreed, enough so that for a while ornithologists considered them a single species.
posted by Johnny Assay at 3:57 PM on September 10, 2005

The Wikipedia article on Ligers makes mention of a Wolphin, a cross between a bottlenose dolphin and a false killer whale.
posted by xiojason at 4:20 PM on September 10, 2005

Heck, there's a bunch listed in the Hybrid article.
posted by xiojason at 4:35 PM on September 10, 2005

My African Cichlids have interbred, although I've read they only do this in captivity. The hybrids turned out to be very pretty. The aquarium hobby tends to frown on this sort of thing, but it was unplanned, and I kept the fish. Here is some info.
posted by drobot at 6:33 PM on September 10, 2005

mcwetboy: I don't understand why the distinction between 'breed' and 'species' bothers you. You have to remember that these are artificial, human-made distinctions.
posted by Eamon at 8:42 PM on September 10, 2005

I'm too tired to search for them all, but there are examples of hybrids in the Sibley Guide to Birds, such as a Scaled and Gambel's Quail hybrid.
posted by DakotaPaul at 10:42 PM on September 10, 2005

A rental stable I went to when I was about 10 had a turken.
posted by brujita at 10:43 PM on September 10, 2005

Seems to be a lot more common among waterfowl, BTW.
posted by DakotaPaul at 10:43 PM on September 10, 2005

Best answer: > Certain species of freshwater fish can interbreed, for example, swordtails and guppies.

I think that would be swordtails and platys (Xiphophorus helleri and X. maculatus respectively.) The platy used to be Platypoecilus but got revised into Xiphophorus because (among other reasons) the two could clearly interbreed and so were definitely-fer-sure not in different genuses. Different species, maybe. (Guppies do sometimes hybridize with mollies and produce fertile F1 hybrids.)

Ernst Mayr led the way in defining species as groups that can't interbreed, and explaining how such non-interbreeding groups might arise from a single parent population. That was a major advance (Darwin called evolution "the origin of species" but never got around to saying how species originate.) Mayr claimed speciation was due to geographic isolation--part of a breeding population gets split off from the rest by an accident of geography (e.g. a bay becomes a lake, a peninsula becomes an island,) the mutations that occur in that sub-population are restricted to that sub-population, and eventually the members reach the point of being reproductively isolated from the parent population by the strictest criterion, isolation by physiology.

Since Mayr, field biologists have muddied the water greatly, by reporting what is actually found in nature. There turn out to be many different kinds and levels of reproductive isolation, between what look like perfectly good species, that nevertheless fall short of the extreme of isolation by physiology. Pertinent to the swordtails/platy example there is reproductive isolation by ecological niche. Swordtails and platys inhabit the same Central American streams, but they don't interbreed in the wild (well, never say never; but if it happens it's vanishingly rare.) Their behavior and ecology is different enough so they simply don't hang out together in the same water. The potential for interbreeding wasn't known until examples of the two groups got crammed together in the same little aquarium, which doesn't have a lot of different ecological regimes into which the fishies might sort themselves by preference.
posted by jfuller at 6:28 AM on September 11, 2005

Related: Ring Species
posted by Leon at 7:17 AM on September 11, 2005

I realize the OP wanted to know about fish and birds, but this article on hybrid mammals is so extensive and interesting that it's worth a link.
posted by ikkyu2 at 11:00 AM on September 11, 2005

Xiphophorus birchmanni and X. malinche (both swordtails, although X. birchmanni essentially lacks a proper "sword tail") can hybridize in the wild...hybrids have been found in the Rio Calnali in Mexico. The theory for why this occurs is based on increased difficulty in chemical communication and thus species identification.
posted by TurkishGolds at 7:04 PM on September 30, 2005