Indo-Pacific bottlenose dolphins pay great attention to their skin care routine, which primarily involves using coral mucus. They rub their bodies against specific types of corals and sponges that are thought to possess medicinal properties. Toadstool leather coral, gorgonian coral, and sea sponge are the three invertebrates that these dolphins are particularly attracted to.
Scientists have discovered seventeen bioactive compounds produced by the aforementioned corals and sponges. These include antibacterial substances and antioxidants, as well as hormone-like compounds that could help maintain skin hydration and elasticity. Some of these corals even produce small amounts of toxic compounds that could eliminate parasites residing on the skin’s surface.
In some instances, dolphins take corals into their mouths and shake their heads, causing a brightly colored substance to emerge. This forms a cloud-like mist around the dolphin, which then swims through it, similar to a person using a perfume spray. By regularly coating their silver-gray bodies with these compounds, dolphins can perhaps prevent and treat skin infections while also maintaining their skin microbiomes – the community of microorganisms living on their skin.
Dolphins even exhibit a sense of orderliness with this skincare behavior, lining up and taking turns to engage with the coral or sponge. When dolphins push or brush against particular corals, the corals secrete mucus that adheres to their skin. This behavior appears to be taught to their young as well, with scientists noting that dolphins perform these rituals after waking from a nap.
In Florida, there are three primary coral reef areas – the Florida Keys, the southeastern coast from northern Monroe County to Palm Beach County, and the Florida Middle Grounds in the eastern Gulf of Mexico. Although southwest Florida is not known for its coral reefs, dolphins in this region employ other methods for skin exfoliation, such as riding boat wakes, brushing up against the sandy sea floor, and rubbing against seawalls.