Self-medication is surprisingly common in the animal kingdom. Many animals, from ants and bees to orangutans, chimps, and, of course, humans, have learnt to employ items from their environment to treat their ailments. Now it appears even bottlenose dolphins have joined the queue at nature’s pharmacy, as they have been seen rubbing themselves against corals in an apparent attempt to heal skin ailments. The discoveries, which were published in Parasitology, were made possible by Angela Ziltener, a wildlife scientist at the University of Zurich, who braved the water to gain the dolphins’ confidence and observe their behavior up close.
When Ziltener witnessed a pod of Indo-Pacific bottlenose dolphins rubbing up against coral in the Northern Red Sea, Egypt, 13 years ago, he realized what they were up to. In a statement, Ziltener stated, “I hadn’t seen this coral rubbing activity reported previously, and it was evident that the dolphins understood exactly which coral they wanted to utilize.” “There must be a reason,” I reasoned.
After being welcomed by the dolphins, Ziltener and colleagues were able to see which corals the dolphins were rubbing against, as well as the impact this was having on both the animals and the reef species. They noticed that rubbing against the coral was irritating the invertebrate polyps that dwell within it, causing them to produce mucus as a result.
The researchers returned to the lab with coral samples in hand so that lead author Gertrud Morlock, an analytical chemist at Justus Liebig University Giessen in Germany, could examine the items they were concealing. They found gorgonian coral (Rumphella aggregata), leather coral (Sarcophyton sp.), and sponges in their haul (Ircinia sp.). In the lab, the three reef species produced 17 active metabolites with antibacterial, antioxidant, hormonal, and poisonous characteristics. The dolphins appear to be using the bioactive substances in the coral species’ exudates to make their skin happy, similar to how we humans enjoy to rub snail snot on our faces.
“The active metabolites come into touch with the dolphins’ skin through repeated rubbing,” Morlock explained. “These metabolites may aid in skin homeostasis and may be effective for microbial infection preventive or supplemental therapy.” According to Morlock, the dolphins’ usage of the coral rub station is comparable to washing or brushing their teeth since they replenish mucus scrubs throughout the day. The researchers aim to keep researching the behavior to learn more about what diseases or body areas the various coral rubs can heal, but they are concerned that the pod and other dolphins are being endangered by rising disturbance from tourists who want to swim with the animals for fun.
“The tourist sector earns a lot of money today from dolphin swimming,” Ziltener explained, “so they’re figuring out which reefs they utilize and maybe upsetting the dolphins if they don’t follow the standards for how to approach them responsibly.” Her work with the Dolphin Watch Alliance, a conservation organization, aims to educate tour companies so that coral reefs and the species that call them home may obtain the required protection to fund additional study and, most importantly, safeguard the animals’ futures.
