Observation of an Attack by a Cookiecutter Shark (Isistius brasiliensis) on a White Shark (Carcharodon carcharias)

Cookiecutter sharks (Isistius brasiliensis) are known to attack a wide array of large animals including pelagic fishes, cetaceans, and pinnipeds. Here we add another top predator, the white shark (Carcharodon carcharias), to the list of potential victims. A subadult male white shark off Guadelupe Island, Mexico, was observed with a fresh cookiecutter shark bite next to its mouth, as well as a second crescent-shaped scar. A subadult male white shark was tracked in the same location and showed diel changes in depth, with the shark occupying shallow water (<50 m) at night, which may be when white sharks overlap with the vertical distribution of cookiecutter sharks. This further indicates that the majority of co-occurring marine top predators can be targeted by cookiecutter sharks.