The forest, a pharmacy for monkeys

Olivier Kaisin is a doctoral candidate at the University of Liège.

Have you ever seen your cat or dog eat grass to aid digestion? ? This is called zoopharmacognosy or, more commonly, animal self-medication. A multitude of wild species use natural substances to prevent and control diseases or to repel pests.

This practice, which can therefore have prophylactic or therapeutic functions, brings together a wide variety of behaviors, such as the consumption of medicinal plants, geophagy or the application of substances in the body. For example, several species consume soil to acquire essential minerals, but also to facilitate their digestion.

Among mammals, zoopharmacognosy is well known in primates, but it is also seen in elephants, bears, elk, as well as several species of carnivores.

In the primatology laboratory of the State University of São Paulo (Unesp), in Brazil, our team studies the behavioral ecology of the rump lion tamarin (Leontopithecus chrysopygus). It is a small primate from Latin America, endemic to the Brazilian Atlantic Forest and currently threatened with extinction.

A part of this project, the object of my thesis, focuses on the study of the physiological and behavioral responses of tamarins in the face of fragmentation and the decline in the quality of their habitat.

An anti-inflammatory resin

In the field, we followed several groups of tamarins, within different fragments of the Atlantic Forest, in order to collect behavioral data and fecal samples to later submit them to hormonal analyses. Normally, we wake up at dawn and follow the tamarins as soon as they leave their perch, until they go to sleep, just before sunset.

During one of these tamarin monitoring groups, we were able to observe them rubbing their body on the trunk of a tree covered in resin. At first, we thought that the tamarins marked their territory, a very common behavior in this species. But we soon realized it was something else. In fact, the individuals of the group collectively rubbed themselves in the region of the trunk from which the resin emanated and also coated their fur with it. Our first reflexes were to record the scene and take samples of the bark and resin to identify the essence of the tree.

A golden-rumped lion tamarin. Wikimedia Commons/CC PER 2.0/Ruth Flickr

When we brought the bark sample back to our local host family, who host us during our field trips, the hostess immediately recognized the unique scent of this tree, which the locals call cabreúva. In fact, the resin produced by this essence has a very woody aroma with shades of cinnamon, cloves, honey and pine. Our expert botanist later confirmed that it was a species of cabreúva, Myroxylon periferuma tree well known in traditional medicine for its healing, antibiotic, anti-inflammatory and antiparasitic properties.

Ten species observed

Since the use of this tree by the tamarins is relatively intriguing, we decided to place camera traps at the foot of the cabreúvas to record future visits by the tamarins. We installed camera traps in three different locations: Morro do Diabo State Park and in two forest fragments, in Guareí and Santa Maria. Camera trap recordings have surprisingly shown that many mammals living in the Atlantic Forest actually visit the cabreúvas.

A total of ten different species were observed rubbing or licking the resin exuded from the trunks of these trees. Among these, several emblematic species of neotropical biodiversity, such as the ocelot, the giant anteater, the ring-tailed coati, the gray-headed marten, the white-lipped peccary or the red daguet.

Heal your wounds and ward off the parasites »

For many of these species, this is the first time that self-medication-like behavior has been observed and described. For example, anteaters use their massive claws to rip open the bark and stimulate resin secretion before rubbing their bodies against the bare trunk. Even more incredible, peccaries spread resin on their skin in pairs and from head to tail. In general, species seem to frequent the tree specifically to acquire this resin and benefit from its many virtues.

Although more studies are needed to identify the resin properties sought by animals and thus confirm that it is indeed zoopharmacognosy, the use of this essence in traditional medicine suggests that mammals visit cabreúvas to heal your wounds and ward off parasites. For lion tamarins, the use of resin cabréúva could play an important role in the fight against yellow fever, a mosquito-borne disease that is decimating primate populations.

The cabreúva could, therefore, represent a common and universal pharmacy for the residents of the Brazilian Atlantic Forest. Myroxylon periferum it is likely a valuable – and contested – resource that could help the species that use it maintain their populations by improving their health and increasing their reproductive success. This discovery may have an important conservation interest, as the disappearance of this species in degraded forest fragments can harm the survival of certain species.

This opinion piece was originally published on The Conversation website.

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