A new study by a team of biologists at the University of Zurich in Switzerland, published in the journal iScience, found that Indo-Pacific bottlenose dolphins rubbed some of their body parts against certain sponges and corals to self-medicate skin ailments. “It’s very intensive,” said Angela Ziltener, one of the study’s lead authors. “They don’t just go through [the coral] – they go up, they come back down again and they rub their belly, their ventral area and the back.”
Dolphins are known to have thick skin that is prone to ailments like yeast and bacterial infections as well as viral pox infections which are expected to become worse with global warming of the oceans.
As part of the study, the team of researchers has surveyed 360 Indo-Pacific bottlenose dolphins that live in the northern Red Sea since 2009. The team was able to witness dolphins queuing up to rub themselves against corals right after waking up and right before they went to sleep. Interestingly, the rubbing motion also seemed to cause the corals to release a polyp mucus.
While the group of dolphins seemed to return to the same coral species, they were also carefully choosing which body parts to rub on them. The team of scientists tested 48 samples of sponges, corals and coral mucus that the dolphins preferred and found that “the presence of bioactive metabolites accounts for this selective rubbing behavior”, according to the study.
It further read: “The three invertebrates preferentially accessed by the dolphins, collected and analyzed by hyphenated high-performance thin-layer chromatography contained seventeen active metabolites, providing evidence of potential self-medication. Repeated rubbing allows these active metabolites to come into contact with the skin of the dolphins, which in turn could help them achieve skin homeostasis and be useful for prophylaxis or auxiliary treatment against microbial infections.”
The compounds found in the corals and sponges are not yet used in antibiotics but the research shows that corals and sponges might hold important medicinal properties.
Gertrud Morlock, a lead author of the study, explained: “Such metabolites are helpful if you have an infection. If the dolphins have a skin infection, these compounds could have something like a healing property.”
Further research is now needed to establish whether the medicinal properties of the corals and sponges actually positively impact the dolphins’ health, while finding out the exact relationship between the different corals and their abilities to alleviate ailments.
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Photography courtesy of Ocean Image Bank / Ron Watkins & Toby Matthews.