EVIDENCE FOR CHEMICAL COMMUNICATION IN PRIMATES

The mammalian olfactory system is specialized for the perception of chemical compounds that regulate a number of functions. The pheromone is the chemical compound most used among species, its effects being either physiological of behavioral, depending on the message transmitted and the context in which it is perceived. Chemical communication by pheromone in mammals is important for regulating reproductive processes and affecting social interactions within populations. Mammals' most active pheromones are usually found in urine and vaginal secretions. These chemical compounds are perceived via the olfactory epithelium and the vomeronasal organ, which have neural connections with different brain nuclei associated with reproductive regulation and emotions. Yet, it remains controversial whether pheromones are present in Old World anthropoids and humans. Altough in other primates, such as prosimians and New World monkeys, chemical communication is acknowledged in territorial marking, conspecific recognition and socio-sexual behavior. There is still disagreement if in catarrhines, pongids and humans, pheromones participate in sexual attraction. First, because this primates have a small olfactory region, both nasal and neural, when compared to the rest of the mammals. And second, because to date the functionality of the vomeronasal organ, seemingly specialized in pheromone perception in mammals, is considered vestigial in catarrhine monkeys and apes. Some recent works provide evidence that in humans such organ is not vestigial, as it was considered, being a specialized structure in the perception of pheromones which are able to promote sex-dependent physiological changes.