Intestinal eversion in a pelagic shark evokes chase and bite attempts by large-bodied carangid fish

Abstract

Expelling indigestible objectives through the cloaca is an important cleansing behaviour for several species of higher vertebrates. Although intestinal eversions are short in duration and rarely observed in free-ranging predators such as sharks, exposed intestines are vulnerable to attacks by smaller predators exploiting ejected digested material. Here we describe the first published record of an intestinal eversion in an oceanic whitetip shark (Carcharhinus longimanus) followed by chase and bite attempts by rainbow runners (Elagatis bipinnulata) in the northern Red Sea, Egypt. This observation provides additional evidence that intestinal eversion occurs in free-ranging sharks and can last for an extended time (> 2 min), likely increasing the potential for attacks by smaller predators.