Red-Fronted Lemurs Use Crushed Millipedes to Soothe Threadworm Affected Anuses

Primate researcher Louise Peckre has published findings that show how Madagascan Lemurs create drugs from millipedes.
Jessica Miley

Animals using plants to treat illness, help capture prey or keep safe is well documented. But the recent research completed by Louise Peckre of the German Primate Centre, in Göttingen, shows a rare example of animals using other animals as a type of pharmaceutical. The primate researcher has discovered that red-fronted lemurs use crushed millipedes to treat threadworm infestations in their guts.

Red-fronted lemurs observed occasionally rubbing insects on their butts

Peckre was observing red-fronted lemurs in the Kirindy Forest, in Madagascar, when she noticed that some of them were chewing on millipedes before rubbing the millipede juice on their anuses and then swallowing the remains of the insect.

Millipedes don’t bite like their close relative the centipede, however, they do contain a chemical called benzoquinone which can blind, burn and poison would-be predators. After close observation, Peckre discovered that the lemurs were using the benzoquinone-rich millipede to treat threadworm infestations.


Threadworms are common in the species and cause severe irritation, they emerge from their victim's assholes at night and then lay eggs on the soft, furry area around their lower back. In the morning the suffering lemurs experience intense itching at the egg site, the animals scratch the eggs and even bite them.

When the eggs get on the lemur's fingers or tongue, it is then often swallowed or passed onto other animals during grooming sessions. Once swallowed the cycle begins again.

The clever lemurs treat the threadworm infections by masticating the insects to extract their juice then wiping it on the itchy areas of their bottom. They then swallow the rest of the insect in an attempt to kill the infestation in their guts.

Lemurs create their own pharmaceutical with millipede juice

Humans do a similar thing when struck by threadworms, treating them with a dose of benzimidazole, which is similar in structure to the millipede's benzoquinone.

Derek Hennen, an entomologist studying millipedes at Virginia Tech, said the vigorous rubbing the lemurs use is a smart tactic.

“Millipedes will secrete more toxins when continually disturbed,” says Hennen. “If they immediately erupted in toxins upon the slightest bump, it wouldn't be a very good defense because it takes time to make new toxins.”

Animals proven to be clever chemists

Peckre has published her findings in a recent issue of Primates. She says the next step in the research is to determine if the benzoquinone from the millipedes kills or deters specific parasites colonizing the red-fronted lemurs.

Using plants for medical purposes is not uncommon in the animal kingdom. For example, pregnant elephants have been observed eating particular leaves to induce birth. In other cases, birds have been noted to weave insect repellent plants into their home to ward off bugs and fruit flies have been shown to choose their homes in matter rich in ethanol as a means of driving away parasitic wasps.