TOXIC toads on the Japanese island of Ishima are losing their evolutionary battle with snakes.
Most snakes, and indeed most other animals, avoid eating toads because of the toxins in toad skin. Rhabdophis tigrinus snakes, however, not only can stomach the toxins, they use them as a weapon to defend themselves.
Deborah Hutchinson, of Old Dominion University, Norfolk, Virginia, and colleagues, found that snakes on Ishima had bufadienolide compounds – toad toxins – in the nuchal glands on the back of their necks, whereas snakes living on the toad-free island of Kinkazan had none.
The snakes can’t make their own toxins, so…
