African rodent uses lethal toxin from a plant for defense

Source:  Wikipedia

The ingenuity of animals is amazing. The African crested rat uses a 'poison arrow' toxin to deter attack.

Woe to the clueless predator trying to make a meal of the African crested rat, a rodent that applies poisonous plant toxin to sponge-like hairs on its flanks, a discovery recently made by Jonathan Kingdon and colleagues from the National Museums of Kenya, the Wildlife Conservation Society, and University of Oxford.

In the only known instance of a mammal acquiring a lethal toxin from a plant for defense, the researchers have discovered where the African crested rat (or maned rat) gets its poison: the Acokanthera tree, the same source used by East African hunters for poison arrows.

The study appears online in the Proceedings of The Royal Society B. The authors include: Jonathan Kingdon, Chris Holland, Tom Gheysens, Maxime Boulet-Audet, and Fritz Vollrath of the University of Oxford; Bernard Agwanda of the National Museums of Kenya; and Margaret Kinnaird and Tim O'Brien of the Wildlife Conservation Society.

"The African crested rat is a fascinating example of how a species can evolve a unique set of defenses in response to pressure from predators," said Dr. Tim O'Brien, Senior Scientist of the Wildlife Conservation Society and a co-author on the study. "The animal and its acquired toxicity is unique among placental mammals."

Scientists have long suspected that the African crested rat is poisonous, primarily due to the animal's specialized behavior, such as exposing a black-and-white coloration on its flanks when threatened by predators, and accounts of dogs becoming ill or dying after encounters with rats. The new discovery concerns the nature of the chemical defense. Instead of producing poison itself—as is the case with poisonous mammals such as the duck-billed platypus and solenodon—the African crested rat finds its toxin (called ouabain) in tree bark.