The vomeronasal organ (VNO) is one of evolution’s most direct enforcers. From its niche within the nose in most land-based vertebrates, it detects pheromones and triggers corresponding basic-instinct behaviors, from compulsive mating to male-on-male death matches. A new study from the Stowers Institute for Medical Research, published online in Nature Neuroscience on July 29, 2012, extends the scientific understanding of how pheromones activate the VNO, and has implications for sensory transduction experiments in other fields.