Ectoparasitic arthropods may be deterred from feeding on certain vertebrates by substances endogenously produced in the skin, pelage or plumage. Deterrent chemicals may also be acquired by vertebrates by rubbing against exogenous sources, i.e. anointing. Monkeys and birds rub themselves with millipedes that defensively discharge benzoquinones. Laboratory bioassays showed that three benzoquinones in millipede secretions deterred ticks by repellency, toxicity and behavior alteration.