New research, published July 30 in the journal Primates, suggests that red-fronted lemurs (Eulemur rufifrons) apply millipede secretions to parts of their bodies, a process called “self-anointment.”
“Self-anointment combined with eating millipede secretions may be a way of self-medication by red-fronted lemurs,” Louise Peckre, a primatologist at the Leibniz Institute for Primate Research in Göttingen, Germany, and the study’s lead author, said in a statement.
In 2016, Peckre was in the midst of several months of field observations of red-fronted lemurs, a near-threatenedspecies according to the IUCN, in central Madagascar’s Kirindy Forest, when hordes of millipedes exploded from dormancy. Kirindy is dry most of the year, but during the Southern Hemisphere’s summer, it gets hot and rainy for a few months. This first substantial rain of the season probably spurred the appearance of the millipedes.
Right after this happened, Peckre watched as six lemurs, from two different groups, made apparent use of the bounty. A lemur would grab a millipede and chew part of it, creating an orange substance as it mixed with saliva. The lemur would then rub its fur and the area around its genitals, including the anus. Then it would bite the millipede again and repeat the sequence, typically switching the hand it held the millipede in, back and forth. Sometimes, though not always, the lemur would then eat the millipede.
Researchers think that self-anointing, which other animals also do, might be a form of communication. But in this case, the authors report that members of the self-anointing lemur’s group, who were close by, didn’t pay much attention to the process. And it didn’t appear that the millipede was a favorite source of food, either.
Evidence from Peckre’s observations did indicate that the lemurs using the millipedes had afflictions that they were trying to treat.
“Strikingly, during the fur-rubbing observations, we noticed the presence of bald areas on the lower back of many animals,” Peckre said. These are known as sit spots, and are likely caused by frequent scratching, she added.
“These bald areas may then indicate the presence of infections by Oxyuridae” — a family of worms — “in the population at the time,” Peckre said.
Pinworms, which can cause anal itching in humans, are also members of the Oxyuridae family.
Peckre and her colleagues hypothesize that the external application of the millipede secretions could be both atreatment for current infections and protection against others. Millipedes harbor a host of compounds to make them less desirable as prey, including benzoquinone, a chemical that keeps mosquitos away and kills bacteria.
Other research suggests that benzoquinone could slow the growth of parasites in the intestine, which might be why the lemurs occasionally ate millipedes that they had first used to treat themselves externally.
Peckre, L. R., Defolie, C., Kappeler, P. M., & Fichtel, C. (2018). Potential self-medication using millipede secretions in red-fronted lemurs: combining anointment and ingestion for a joint action against gastrointestinal parasites? Primates, 1-12.