Snakes eat poisonous toads and collect their poison

The Rhabdophis tigrinus snakes that reside on the island of Ishima, Japan, eat poisonous toads and store the toxic venom in glands for its own defense. While the monarch butterfly also collects defensive poison from plants and frogs sometimes beef up their defenses with bug toxins, herpetologist Deborah Hutchinson of Old Dominion University says it's very rare for a vertebrate to do so. From Scientific American:

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Some R. tigrinus snakes carry toxins called bufadienolides in their nuchal glands, sacks located under a ridge of skin along their upper necks. When threatened, they arch their necks, exposing the poisonous ridge to an antagonist. The clawing and biting of hawks and other predators most likely rips the skin and lets the poison ooze out, potentially blinding the snake's attackers, says herpetologist Deborah Hutchinson of Old Dominion University in Norfolk, Va. "It might not kill the predator but it would be noxious enough to deter predation," she says.