Epibionts and symbioses of cetaceans: barnacles, whale lice, remoras

A large cetacean is never entirely alone: it carries a whole retinue of organisms. Barnacles cemented to the skin, “whale lice” tucked into the folds, remoras hitching a ride, diatoms yellowing the epidermis… every whale is a mobile ecosystem.

The widget above distinguishes commensals (simple passengers), parasites and mutualist partners. It shows, for instance, that the famous white callosities of right whales are in fact colonies of small crustaceans, or that a humpback whale can carry several hundred kilos of barnacles.

Commensalism, parasitism and mutualism

The relationships between a cetacean and its guests illustrate the main types of symbiosis. In commensalism, one partner benefits without harming the other (barnacles carried towards plankton-rich waters). In parasitism, one gains at the other’s expense (whale lice, the cookiecutter shark). In mutualism, both find an interest in it (cleaner remoras).

The build-up of attached organisms, known as biofouling (biological fouling), has a hydrodynamic cost: barnacles and diatoms increase drag. It is one of the hypotheses put forward to explain some breaching and rubbing on the bottom, which also help to dislodge these passengers.

Going further: explore the interactive anatomy of cetaceans and the pathologies that affect them. All our tools are gathered in the explorer.