Why do dolphins rub against corals?

Self-medication in animals is no longer a strange phenomenon! It is therefore not surprising to see dolphins practicing it! This is the observation that an international team of researchers has just made. Their findings were published in the journal iScience.

Doing regular dives with dolphins in the Indo-Pacific, one of the authors of the study was challenged by an unusual behavior. The dolphins used to rub against corals and sponges, upon waking up and just before sleeping. Even more amazing. This is a behavior that dolphins teach newborn babies. But why ? Is it a “beauty” routine? Not exactly !

Read also: What if the corals died? Although coral reefs only inhabit a small part of the ocean surface, they are, on the other hand, home to a quarter of marine biodiversity! Victims of global warming…

Dolphins would use coral slime to their advantage!

The researchers chemically examined the compounds secreted by the coral against which the dolphins rub. What are these animals interested in? The slime! It is released by two types of coral and a sponge: gorgonian coral, leather coral and Ircinia sponge.

Thanks to an analysis using a chromatography technique, the researchers identified a cocktail of bioactive compounds. The latter are antimicrobial, hormonal and have cytotoxic properties. The researchers therefore asked themselves the following question. Do dolphins use them to heal themselves?

Self-medication is common among so-called “intelligent” animals. It has been observed in chimpanzees or birds for example. What about dolphins? Until today, experts were not able to affirm that the dolphins practiced self-medication.

Self-medication in dolphins is certainly plausible. I I wouldn’t be at all surprised if that were the case.” – Jaap de Roode, expert in animal self-medication.

This new study suggests that microorganisms found in corals and sponges may help treat skin conditions. And even infections. Nevertheless, the evidence put forward by the study is not yet sufficient. Indeed, other reasons could explain this strange behavior observed in dolphins. For example, this could simply allow them to scratch or camouflage themselves.

Currently, it is not yet possible to take skin samples from dolphins due to the regulations that protect them. But the research will not stop at this stage. For the next steps, the researchers want to observe whether this behavior is practiced by dolphins from different regions.

Read also: Insects to treat a wound, a way of self-medication in chimpanzees?

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