They found that to make its poison fur, the rat — which averages about 14 inches (36 cm) long — chews the bark of the A. schimperi and licks itself to store the resulting poisonous spit in specially adapted hairs. This behavior is hardwired into the animal’s brain, similar to nitpicking behavior of birds or self-bathing of cats, the researchers suspect.
They have no idea why the rat doesn’t die from the poison itself.