Will pack rats pack it in?

• Position: Warming Temperatures

When temperatures get warmer, woodrats suffer a reduced ability to live on their normal diet of toxic creosote, suggesting that global warming may hurt plant-eating animals, according to lab experiments at the University of Utah, Salt Lake City.

"This study adds to our understanding of how climate change may affect mammals, in that their ability to consume dietary toxins is impaired by warmer temperatures," says Denise Dearing, distinguished professor and chair of biology. 'This phenomenon will result in animals changing their diets and reducing the amount of plant material they eat, relocating to cooler habitats, or going extinct in local areas."

Adds the study's first author, biology doctoral student Patrice Kurnath: "We found that these woodrats, which are nocturnal desert dwellers, have a harder time eating their natural diet at slightly warmer temperatures. In terms of climate changes, this study suggests that plant-eating animals all over the world may have problems with their preferred food sources."

While not all animal diets are as toxic as those of woodrats and other rodents that eat plants like creosote bushes or juniper, most mammals have some toxins in their diet. In an ongoing evolutionary battle, plants evolve chemical defenses against being eaten and animals evolve liver enzymes or other ways to overcome...