Similar to humans, dolphins sometimes struggle with skin irritations.
However, rather than putting on a soothing cream, the Indo-Pacific bottlenose dolphins that live in the northern Red Sea go to the nearest coral reef to heal themselves.
They line up and rub against the sponges and corals. And, some of these organisms may do much more for the dolphin than being a scratching medium.
A recent study published in iScience notes that a team of international researchers concluded that the mucus being released from some of these corals and sponges contains antibacterial properties and other potentially soothing substances.
Dolphins Self Heal Themselves by Rubbing against Mucus-Oozing Corals
The team emphasizes that the dolphins gather near these invertebrates to alleviate their skin infections.
Though rubbing has been seen in other cetaceans like beluga whales and orcas, evidence of dolphins doing it is rare.
Therefore, the dolphins that visit reefs off the Egyptian coast have gotten so much attention from both tourists and researchers and were even featured in one BBC documentary Blue Planet II episode.
This attitude is much more complex than it looks, according to the co-author of the study, Angela Ziltener, a marine biologist at the University of Zurich.
She monitored around 360 bottlenose dolphins in the Red Sea since 2009. While diving, she realized that the dolphins did this unique rubbing thing with some corals and she started to wonder what was really going on.
Picky with the Corals & Specific with the Rubbing Body Parts
The team explains that the dolphins seem to be picky with the corals and sponges they choose for the rubbing. And, they seem to rub only certain parts of their body onto specific specimens.
They scratch their more sensitive areas with the bushy stalks from the soft gorgonian coral known as Rumphella aggregata, a behavior which the scientists have termed “gorgoning”.
The hardened areas like their tail fluke or head are scratched on the wrinkled surface of a leather coral from the genus Sarcophyton and one species of stiff sea sponge from the Ircinia genus.
Ziltener explains that there are plenty of other corals that these dolphins ignore entirely. There seems to be a relationship between the specific corals and sponges and this species of dolphins.
What about the Oozing Mucus from the Corals & Sponges?
One aspect of this relationship influenced both creatures and it was the mucus. With the dolphins grinding against the sponges and corals, their polyps release fluid that will stain the skin of the dolphin yellow or green.
Interestingly, one dolphin was seen ripping a part of a leather coral and shaking it in the mouth similar to a dog with a chew toy in order to cause the mucus to get out.
To check out the molecules of this mucus, the researchers took samples of gorgonian coral, leather coral, and the Ircinia sponges.
The tests found 17 metabolic compounds that have the power to fight certain bacterial strains and avert damaging processes while balancing the hormones in the skin of the dolphins.
The team claims that the dolphins may deliberately use these sponges and corals to cover their bodies with mucus, similar to what humans do when applying an ointment on a rash.
If this claim turns out to be true, dolphins would be added to a growing list of animals able to self-medicate.
The animal medication world or zoopharmacognosy includes various creatures that use natural remedies to maintain their health. For example, chimpanzees eat leaves to boost their digestion while fruit flies drink alcohol to eliminate deadly parasites.
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