Millipedes are extremely poisonous, but in Madagascar they are gathered with enthusiasm by black lemurs. They don't eat their prize finds, they just annoy them by biting them gently. The millipedes spray out defensive chemicals, including cyanide, which the lemurs spread over their fur. Lemurs crave these dangerous substances and grab every millipede within reach. The poisons are thought to repel insects and keep malaria carrying mosquitoes at bay. As the self anointing ritual continues, the lemurs enter a blissful state. The secretions seem to act as a narcotic, giving the lemur pleasure as a reward. This drug habit must be harmful, but the benefits of the insecticide must outweigh the risks. Millipedes usually survive the experience relatively unscathed, but the lemur takes a little longer to recover.