Whereas the monkeys normally hew to strict hierarchies when it comes to who gets the best food and who grooms whom, there are no obvious top or rotten bananas in the sharing of millipede secretions. The researchers have yet to demonstrate that the use of millipedes prevents bot fly infestation among monkey participants. They also do not yet know if the use of insect repellent is common among capuchins, or is limited to the intensively studied group at the Venezuelan reserve. There, at least, the custom is entrenched, and for all the demonstrated carcinogenicity of benzoquinone, the capuchins do not appear to have suffered long-term consequences from exposure to it, many of them living more than 30 years. As the infant monkeys learn early on, the family that sprays together, stays together.
Some researchers suggest that animals use a variety of plant products.