The chemical MUPpeteer.

Rodents exhibit an innate fear-like behavior when they sense the chemical traces of predators. In this issue, Papes et al. (2010) report that the major urinary proteins (Mups) released by predators are detected by sensory neurons in the mouse vomeronasal organ (which also detects pheromones involved in aggression), triggering a fear response. Copyright (c) 2010 Elsevier Inc. All rights reserved.