This image shows a desert woodrat in a metabolism cage at the University of Utah. The cage allows researchers to measure how much food and water the rat consumes and how much waste it produces.

Caption A captive desert woodrat, also known as a packrat, stands on a rock near branches from a toxic creosote bush. A new University of Utah study shows how microbes in the gut play a key role ...

Fossilized woodrat nests reveal that their diets shifted in step with the expanding desert habitat. While still favoring less hostile fare, over generations, the woodrats ate even more creosote as ...