Rainbow frogs

When we go out into the field to collect frogs, we're actually collecting pairs of frogs as they're mating. We pick them out of the pond, male clinging to the female's back (this is called "amplexus"). Occasionally someone asks if we ever find a male-male pairing or a female-female pairing. The simple answer is "no", we don't. A female-female pairing is extremely unlikely because females use the males' courtship calls to locate them. Females don't do courtship calls, so they wouldn't be able to find each other to pair up. Male-male pairings can be induced by placing two males alone in a container - if another male is there, they'll pair up (don't ask me how they choose who's on top, I have no idea) - but that's an "if all else fails" sort of situation. The closest we've gotten to any sort of queer treefrogs are menage a trois of one female and two males. Presumably a male and female hooked up, and one male was just desperate enough to try to join in.

This is not to say that there are no gay frogs. There are...they just aren't our species.

On a related note, here is a hilarious article about gay animals and religion.