pheromones
A type of hormone meant that is secreted outside the body (unlike most hormones) to elicit a certain behavior to those who can smell it. Among insects, it's one of the primary means of communication and coordination. In mammals, those are primarily used to convey sexual arousal/availability or as a way to mark territory. Also, catnip has an effect on cats because of the pheromones produced by the plant. Until e621…
