Pack rats live in the American Southwest, where they nosh on the native vegetation. Some of these plants produce protective toxins, for example the junipers in the Great Basin desert or the creosote bushes of the Mojave. But pack rats seem to eat these noxious shrubs with impunity.

 

The researchers found that pack rats from the Mojave harbor gut bacteria that can break down creosote. When antibiotics depleted the pack rats’ gut bacteria, the animals suddenly found creosote nearly indigestible.

 

Further, the researchers found that they could take pack rats from the Great Basin—the ones that eat juniper—and give them the ability to eat creosote. All they needed was a fecal transplant, which supplied the necessary gut bacteria from their Mojave-based neighbors. The work appears in the journal Ecology Letters. [Kevin D. Kohl et al., Gut microbes of mammalian herbivores facilitate intake of plant toxins]

 

The findings show the importance of gut bacteria for eating some otherwise dicey foods. They could also allow farmers to expand the diet of their livestock. Cows with the right gut bacteria could feast on what was formerly feh.