Recent footage from a camera trap from Brazil’s Atlantic Forest explores our understanding of the practice of self-healing animals. Researchers in this case have found evidence that many tropical mammals regularly visit certain trees, which are known to play a role in traditional medicine. The work was published in a journal BioTropica.
Olivier Caisin, a PhD student at the University of Liège and the State University of São Paulo, and his team discovered unusual behavior while studying black tamarins. It is noteworthy that the footage from the camera recorded representatives of this species of monkeys, who are not known for their friendliness, visiting the cabriolet (Myroxylon peruiferum) trees in groups.
“We saw a group of tamarins rubbing against this tree, and at first we thought they were marking the smell, marking the territory, because they often do,” says Kaysin. Upon closer inspection, something else was revealed.
This type of tree is commonly used in traditional medicine for various human diseases. Kabrevas produce a resin that is believed to help treat scabies, dysentery and urinary tract infections. At the same time, it is believed that its bark acts as an antibiotic, killing Aedes aegypti mosquito larvae and work as an antifungal agent. It is also used as a perfume because of its distinctive and pungent odor, reminiscent of honey and freshly cut pines, Kaisin says.
The team has set up additional camera traps to investigate what black tamarins do. This showed that the behavior was not limited to this animal.
The host is a mammal
Camera-traps strategically placed on different trees have shown that many animals living in the Atlantic Forest visit cabriots. The list of mammals that have rubbed or licked a tree reads like a roll call of tropical biodiversity: ocelots, thais, coats, non-tropical fruit bats, baker’s collars, northern tamandua and fallow deer.
The authors of the study note that this is the first observation of such behavior in bakers, tamandua, tairos and non-tropical fruit bats. Tamandua, which are a species of anteater, used their elongated claws to tear down the tree before performing the good old rubbing of the whole body, Kaisin says. Meanwhile the bakers groped the snout and rubbed against each other from top to tail, seeming to have split the balm from the wood. “Put on the snout and then on the hind legs. But they also did it between individuals, which was really amazing to see, ”he adds.
Kaysin and his colleagues believe that some of this behavior with wood is an example zopharmacognosy – or self-medication of animals. But this hypothesis has not yet been confirmed. “We make assumptions based on modern literature, but other research is needed to really understand why,” he says. It is possible that Atlantic Forest mammals use tree balm to repel parasites or protect against diseases spread by mosquitoes or ticks.
«[T]the behaviors they see and describe are certainly consistent with self-medication, ”says Dan Bloomstein, a professor of ecology at UCLA who was not involved in the study. “The new thing I’ve been thinking about is using trap cameras and getting all this hidden information, things going on there that people don’t see, and then assuming it’s in line with self-medication.”
Alvaro Mesqua is a doctor of philosophy. a student of the Complutense University of Madrid who studied history zopharmacognosy. He was not involved in the study of the Atlantic Forest and says that various things can motivate the behavior of these animals in relation to the tree. “Sometimes it’s just a matter of taste, something they like to eat, sniff or rub their hair for social or territorial reasons,” he says.
Given that these trees are believed to have a number of benefits, he believes that self-medication is a great opportunity: “[I]It is more than likely that different species of mammals know perfectly well how and when to use them to benefit from their prophylactic and / or therapeutic properties ”.
In general, the field of zoopharmacognosia remains largely understudied, Mezkua says, despite its importance and the potential benefits it can provide for both wildlife and humans. “There are a lot of applications for this in such important areas as veterinary medicine, animal welfare, pharmacology, animal husbandry, human medicine, animal and habitat conservation and much more,” he says.
Based on their findings, Kaysin and his colleagues believe Kabreuvas trees could act as a “universal pharmacy” for Atlantic forest animals. «M. peruiferum can be a valuable and controversial resource for mammalian species that can help maintain populations by promoting their health and fitness, ”the study said. If this hypothesis comes true, this finding could have important implications for the conservation of these species and the Atlantic Forest.
“As a result of further research, once this behavior is definitively confirmed and the capercaillie trees are a natural pharmacology for a wide range of species, conservation measures will be taken and many areas can become protected,” Mesqua said.
Whether these animals depend on wood and how important it may be for their physical shape are just some of the questions that still need to be answered, Kaisin said. His own research project was halted due to the COVID-19 pandemic. But other investigations are underway to confirm whether such behavior is an act of self-medication.
While questions remain as to why these animals flock to these trees, Kaysin is thrilled that we still need to learn a lot about tropical species. “I think in 2022 it’s interesting to still discover some incredible things about species, especially about mammals, because they’re usually more studied,” he says.