These dolphins might be self-medicating

We aren't the only creatures who pop a pill or apply an ointment when we're sick. Chimpanzees swallow leaves to rid their bowels of parasites, and some ants eat food rich in hydrogen peroxide to fight infections. Scientists might add dolphins to the list. The bottlenose dolphins in the Red Sea rub against coral and sponges that have healing powers.

Michael Huffman, a primatologist and expert on animal self-medication at Kyoto University, was not involved with the research.

Since the 1980s, he has studied primate self-medication. He gathers information on the phenomenon across the animal kingdom. The logistical challenges of observing animals at sea made it difficult to study such behavior in the ocean.

The University of ZFC;rich and the Dolphin Watch Alliance have a wildlife biologist named Angela Ziltener. Since 2009, Ziltener has scuba dived in Egypt's Red Sea among a group of dolphins, gaining their trust and observing their behavior up close.

She noticed that the animals were rubbing against the sponges. The dolphins rubbed their heads on some corals and avoided some species altogether. The younger members of the group watched the adult dolphins queue up to rub, while they slowly began to mimic their actions.

The dolphins seemed to be getting more than just a scratch. As they rubbed, mucus coating puffed off the corals and sponges, clouding the water and coloring the dolphins' skin.

She thought mucus could help heal skin ailments. Studies have shown dolphins are vulnerable to infections of poxviruses, which causes ringlike lesions on the skin, and other diseases.

Gertrud Morlock, an analytical chemist at Justus Liebig University Giessen, and Ziltener collaborated to find out if the mucus from the corals had any therapeutic properties. The duo took tiny samples of mucus from the dolphins, which were rubbed on three different surfaces: gorgonian coral, leather coral, and a sponge.

The researchers put the samples on ice and brought them to Morlock's lab, where they used a technique called high-performance thin-layer chromatography to analyze the mucus. The coral mixture could be separated into their component parts by applying chemicals to a special plate.

The scientists separated the mucus into its component chemicals and then tested the parts for healing or therapeutic activities. 17 biologically active compounds were found in the corals and sponge coating. The chemicals could be used to treat skin conditions.

Eric Angel Ramos, a marine biologist at Rockefeller University who wasn't involved with the work, says showing the mucus has healing properties is a good first step. To prove that the animals are self-medicating, I would want to see what kind of skin ailments these dolphins are experiencing, and if these corals actually improve their health.

In his studies, Ramos has seen bottlenose dolphins rub against corals. He wants to look back at his own observations in light of the new findings. The animals could be self-medicating, or they might just like the way the corals feel.