Poison Dart Tree Frog

What you're getting

Scientists still can't quite work out where poison dart frogs get their toxicity from, though the leading theory is that they pick it up from their prey — ants, termites, beetles, that sort of thing. Here's the thing though: poison dart frogs bred in captivity, kept away from the insects they'd normally eat in the wild, never develop any poison at all. Which rather suggests the whole toxic thing depends on what they're eating.