Sharks as exfoliators: widespread chafing between marine organisms suggests an unexplored ecological role

Ectosymbionts, such as bacteria and parasites, are found on the surface of organisms throughout the world's ecosystems. Hosts have evolved a variety of mechanisms across ecosystems to rid themselves of ectoparasites or other skin irritants including chafing behavior, whereby an organism curves their body to rub the convex portion of their body along a rough surface (Eibl-Eibesfeldt 1955; Wicklund 1969; Myrberg & Gruber 1974; Wyman & Walters-Wyman 1985; Mooring et al. 2004; Papastamatiou et al. 2007; Grossman et al. 2009; Ritter 2011; Berth et al. 2017).