Behaviour development: a cephalopod perspective

Abstract

This paper evaluates the development of behaviour from the viewpoint of the intelligent and learning dependent cephalopod mollusks as a contrast to that of mammals. They have a short lifespan, commonly one to two years, and most are semelparous, reproducing only near the end of their lifespan. In the first two months of life, Sepia officinalis cuttlefish show drastic limitation on learning of prey choice and capture, gradually acquiring first short-term and then long-term learning over 60 days. This is paralleled by development of the vertical lobe of the brain which processes visually learned information. In the long nonreproductive adulthood, Octopus species show major flexibility in prey choice and continued mobility across the sea bottom. This results in large behaviour variability within and between individuals and both exploration and simple play-type behaviour. During the short reproductive period, Sepioteuthis sepioidea squid gather for choice and competition, including flexible strategies in use of their skin display system. At the end of the life cycle, Sepia officinalis cuttlefish have a swift decline in memory capacity and also brain degeneration during their short period of senescence. The emphasis on different behaviour capacities during these four stages is contrasted with those of the mammalian model of behaviour development.