Mice 'eavesdrop' on rats' tear signal

Tears might not seem to have an odor. But studies have shown that proteins in tears do act as pheromonal cues. For example, the tear glands of male mice produce a protein that makes females more receptive to sex. Now researchers reporting in Current Biology on March 29 have found that rat tears contain proteins with similar functions. The new study also shows that mice pick up on the rats' tear proteins, too. The chemical cue appears to tip the mice off to the fact that predators (i.e., rats) ar