Snakes bite back at poison toads Snakes in Australia have evolved to counter the threat of invasive, poisonous cane toads, scientists have found. The toads ( Bufo marinus ) were only introduced in the 1930s but have already overwhelmed the local wildlife in Queensland with their rapid reproduction and toxic flesh, which kills many predators foolish enough to make them a meal. But for two species of snake, at least, natural selection has produced a defence: the snakes have developed relatively smaller heads and longer bodies. In essence, the reduced gape of the animals limits their ability to eat the...