Monkeys Are Made of Chocolate

by Jack Ewing

The first clue came from the discovery that dart frogs of all species lose their toxicity when kept in captivity in a terrarium. Suspecting that a variation from their natural diet might be the cause, biologists began to pay close attention to what the colorful amphibians eat in the wild. It turned out that a high percentage of their natural prey was ants. In fact, the least toxic genera of dart frogs, Colostethus, consumes the fewest ants, while the extremely poisonous Phyllobates eats them almost exclusively. Moderately toxic Dendrobates is somewhere in between, with a diet containing 50 to 70 percent ants. Knowing that ants tend to contain a high level of alkaloids and that dart frog toxins are primarily alkaloids, biologists have come to the conclusion that these amazing frogs have “learned” how to concentrate the alkaloids that they acquire from eating ants in the toxic mucous secreted through glands in their skin.