MAMMALS, molluscs and insects all learn to steer clear of food that makes them ill. But vampire bats have lost this ability, known as taste aversion.
Brock Fenton at York University, Toronto, suspects this is because the bats feed exclusively on mammal blood, which is never poisonous. Fenton and his team fed vampire bats (Desmodus rotundus) cinnamon-flavoured blood and then injected them with lithium chloride to make them ill. But the bats never learned to make the connection between the cinnamon taste and poison. Meanwhile, one insect-eating and two fruit-eating bats of related species learned to avoid cinnamon-laced food (Animal…
