Cephalopods as Predators: A Short Journey among Behavioral Flexibilities, Adaptions, and Feeding Habits

Abstract

The diversity of cephalopod species and the differences in morphology and the habitats in which they live, illustrates the ability of this class of molluscs to adapt to all marine environments, demonstrating a wide spectrum of patterns to search, detect, select, capture, handle, and kill prey. Photo-, mechano-, and chemoreceptors provide tools for the acquisition of information about their potential preys. The use of vision to detect prey and high attack speed seem to be a predominant pattern in cephalopod species distributed in the photic zone, whereas in the deep-sea, the development of mechanoreceptor structures and the presence of long and filamentous arms are more abundant. Ambushing, luring, stalking and pursuit, speculative hunting and hunting in disguise, among others are known modes of hunting in cephalopods. Cannibalism and scavenger behavior is also known for some species and the development of current culture techniques offer evidence of their ability to feed on inert and artificial foods. Feeding requirements and prey choice change throughout development and in some species, strong ontogenetic changes in body form seem associated with changes in their diet and feeding strategies, although this is poorly understood in planktonic and larval stages. Feeding behavior is altered during senescence and particularly in brooding octopus females. Cephalopods are able to feed from a variety of food sources, from detritus to birds. Their particular requirements of lipids and copper may help to explain why marine crustaceans, rich in these components, are common prey in all cephalopod diets. The expected variation in climate change and ocean acidification and their effects on chemoreception and prey detection capacities in cephalopods are unknown and needs future research.

Social Media and citizen science provide valuable data for behavioural ecology research: Are cuttlefish using pursuit-deterrent signals during hunting?

“…We suspect that increasing the species (i.e. N > 5 used here) number would produce a significant difference between crustacea and bony fish for adult cuttlefish and is expected amongst mature cephalopods 13,57 like the ones studied here.…”

“…Adults are not obliged to crustacean only diets, unlike juveniles (crustacea are rich in amino acids and polypeptides, essential nutrients for juvenile cephalopod growth 13,57 ), and a varied fish dominant diet becomes of greater nutritional value into adult life [57][58][59] .…”

“…Being both predator and prey is a significant factor for cephalopod behaviour 2 . Subduing, killing, via protein-based neurotoxins 13,78 and assimilating prey is not an immediate process 11 . It can take time, and this makes cuttlefish vulnerable to kleptoparasitism and predation from other predators that can detect and trace signs of an animal being killed and or eaten (i.e.…”

“…Almost all cephalopods (Mollusca: cuttlefish, squid, octopus and nautilus) are voracious mesopredators that hunt a diversity of prey -primarily crustaceans, teleost fish, and indeed other cephalopod species 12,13 . An advanced non-centralised nervous system, coupled to neuromuscular and hydrostatic dermal units requires the neural complexity that appears to also provide cephalopods high levels of cognition, significant (including episodic) memory, complex sensory systems (chemo-, mechano-, and photo-receptors), and real-time body pattern manipulation (i.e.…”

“…deimatic displays). All these attributes are used to locate, identify, and engage prey 13 . Additionally, these unique adaptations are used to determine, and avoid or deter seal, dolphin, shark, and bony fish predators 14,15 via camouflage 16 or warning displays 15 .…”