Unesp Journal | Interest of ten species of mammals in the same tree variety intrigues researchers

Marcos do Amaral Jorge

the cabreúva (Myroxylon peruiferum) is a tree native to Brazil, found in practically the entire territory. It stands out for its solid wood, for its size – it can reach 30 m in height – and for its ability to produce an oleoresin with a pleasant odor, whose prophylactic and therapeutic properties are highly appreciated by traditional communities. But a new study conducted by researchers at Unesp is showing that its popularity may be even greater among the animal kingdom. A video captured by a trap-type camera recorded the moments when several mammals interacted with this tree of the legume family, rubbing, biting and even licking the trunk.

The researchers were intrigued by the variety of animal species that appeared in the video, and by the frequency of occurrences. Among the visitors were groups of collared peccaries and ring-tailed coatis, a solitary bush deer, the nocturnal ocelot (which, in addition to rubbing itself, seems to lick the stem of the tree), bats, the lesser anteater (which arrives climbing on the stem of the tree) and the tayra, one of the species recorded for the first time performing this type of behavior. In some locations, records showed that the cabreúva was visited at least once every two days (see video below).

The originality of the record led researchers from the Rio Claro campus to describe in detail the animals’ interaction with cabreúva balsam, and the article was published at the end of March in the scientific journal Biotropica.

For Laurence Culot, professor and researcher at the Primatology Laboratory of the Biosciences Institute of Unesp in Rio Claro, the observed diversity of species, the high number of visits and the mentions in the literature of the healing, repellent and anti-parasitic properties of the balm produced by cabreúva raise the hypothesis that it is a case of zoopharmacognosy. The term describes the consumption by wild animals of non-nutritional plants present in their natural environment for the purpose of controlling or preventing diseases or eliminating parasites. But at the moment this is just a possibility, explains the researcher.

“To prove that this is a case of self-medication on the part of the animals, it is still necessary to carry out several studies. We have behavioral data and we have data from the literature that prove some properties of cabreúva. The point is to carry out tests that can show that the balm can actually have some effect against mosquitoes, parasites or other pathogens”, says Culot, who is also a professor at the Graduate Program in Ecology, Evolution and Biodiversity at Unesp.

In the scientific literature there are several proven behaviors of zoopharmacognosy, most of them associated with chimpanzees and gorillas. In the case of the researchers from Unesp, the original clue was given by a small primate. Since the beginning of the year, Culot has been developing a research project funded by Fapesp in which he analyzes the resilience of black lion tamarins to human-modified environments and their presence in small forest fragments. During a field activity in which they monitored this species, the researchers noticed that a group of individuals spent more time than usual rubbing around a tree, specifically.

The habit of rubbing against trees, explains the researcher, is quite common among black lion tamarins, either to mark territory or to communicate to other tamarins their stage of reproduction. “The behavior we saw, however, was different. It took longer, about 50 minutes, and involved all the members of the group. Territory marking, on the other hand, is usually done briefly and by just a few individuals,” she reports.

On closer inspection, the researchers noticed the black lion tamarins rubbing their thoracic, abdominal and inguinal regions on areas of the trunk where the balm was deposited on the bark. Sometimes, the tamarins also manipulated the bark of the trunk itself, spreading the balm on their hands and then applying it on their body and tail.

The unusual observations motivated the researchers to install camera traps in order to record the behavior over a longer period of time. In this way, cameras were installed in three fragments of Atlantic Forest in different places in the state of São Paulo where the researchers were following the black lion tamarins.

“When we analyzed the videos, we were surprised to see that other mammals had the same behavior. Each one, in their own way, rubbed themselves and sometimes licked the balm,” says Culot. In some of the places where the cameras were installed, the mammals visited the cabreúva on average once every two days. But in no time, distinct species were seen sharing the tree. For four species of mammals, the tamanduá, the anteater, the collared peccary and the bat, it was the first time that a behavior of this type was recorded in the scientific literature.

The observations open at least two avenues for future research. The first involves finding a more direct way to prove the balm’s therapeutic or preventive benefits to the black lion tamarin. Another way would be to involve the relationship between cabreúva and other species that inhabit forest fragments. “It would be a complex research, but we could investigate how the presence of this tree in the Atlantic Forest fragments affects the health of other species. For example, would the animals have fewer parasites in places where there are more cabreúva trees?”, he suggests.

Image above: sighting of ocelot and cabreúva in Morro do Diabo State Park. Credit: Primatology Laboratory Unesp/Rio Claro.

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