Plant – animal warfare has been played out over millions of years. Plants produce toxins (or secondary plant metabolites) and animals find ways to detoxify or excrete them. Now a study, by Denise Dearing and colleagues, published in Functional Ecology in 2011, suggests that some species of desert woodrat may also moderate their intake of poisons by eating less and drinking more. Though they haven’t pinned down the mechanisms, they suggest that maybe receptors in the gut may regulate plant consumption in these woodrats (who tend to have a general diet, consuming lots of different plants – and plant toxins). Additionally, they find these rats drink more water – possibly a mechanism to aid in flushing toxic chemicals from the system.
For more see “Differential regulation of plant secondary compounds by herbivorous rodents” by Ann-Marie Torregrossa, Anthony V. Azzara, and M. Denise Dearing in Functional Ecology Volume 25, Issue 6, pages 1232–1240, December 2011 and here.