A bitter taste in your . . . stomach

Animals quickly learn to avoid most foods with a bitter taste because these often contain dangerous toxins. Bitterness “is a signal telling us that something is quite wrong in the food we’ve ingested,” says Enrique Rozengurt of the University of California, Los Angeles School of Medicine.

It’s a handy protective mechanism, and animals may depend on more than their tongues to detect bitter substances, Rozengurt and his colleagues find.