Cannibalistic attack by Octopus vulgaris in the wild: behaviour of predator and prey

Cannibalism refers to consuming a conspecific and is common in many taxa. In addition to conferring advantages for a predator’s growth, reproductive efficiency and survival (e.g. elimination of future competitors, ready supply of high-quality nutrition and of optimal proportions of vitamins, minerals and amino acid), cannibalism is an important link between individual and population-level processes (Claessen et al., 2002). Based primarily on the study of stomach contents, Ibañez & Keyl (2010) have shown that cannibalism is widespread in cephalopods. Cannibalism thus potentially may be an important component of natural mortality (Claessen, De Roos & Persson, 2004), and natural mortality is a key factor in the limitation of populations and management of exploited resources. Cannibalism in octopuses has been recorded only infrequently (Ibañez & Keyl, 2010), and available anecdotal observations of cannibalism in the wild are confined to sexual cannibalism (e.g. Hanlon & Forsythe, 2008; Huffard, Caldwell & Boneka, 2010; Huffard & Bartick, 2014)....