Tags: Protein.
Pheromones have evolved in all animal phyla to signal sex and dominance status and are responsible for stereotypical social and sexual behaviour among members of the same species. In mammals these chemical signals are believed to be detected primarily by the vomeronasal organ (VNO) a chemosensory organ located at the base of the nasal septum.The VNO is present in most amphibia reptiles and non-primate mammals but is absent in birds adult catarrhine monkeys and apes.