Desert rodents cope with toxic diets

Researchers say wood rats in the U.S. Southwest survive while eating toxic plants by doing what human dieters do -- eat smaller meals and drink plenty of water."For decades, we have been trying to understand how herbivores deal with toxic diets," University of Utah biology Professor Denise Dearing said. "We are interested in knowing how the rats adjust their toxin intake so they don't poison themselves and die," Dearing said. "They live in deserts where plants evolved toxins to protect themselves, and the wood rats don't have much choice in what to eat." Toxins in a number of desert plants can damage the nervous system, disrupt absorption of nutrients, hinder growth and cause water loss.Some wood rats that can metabolize small amounts of many different plant toxins have actually changed their eating and drinking behavior to avoid an excessive dose of any one plant poison, a university release said Tuesday.In addition to eating smaller amounts and increasing their water intake, researchers said, the animals will increase the time between meals to allow their bodies to metabolize the toxins.