Behavioural aspects of the New Zealand octopus Pinnoctopus cordiformis: acclimation, sleep deprivation and responses to video stimuli
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
The native New Zealand octopus P. cordiformis is a relatively unstudied member of the cephalopod class. Behavioural investigation will widen the breadth of our knowledge about octopus behaviour away from the handful of classically studied species. Here I test the acclimation patterns of P. cordiformis in an experimental environment, using video recording to document and analyse behaviour over a three-day period. I also test P. cordiformis following acclimation, examining the role of sleep in mediating behaviour, and test for the presence of homeostatic regulation on behaviour following sleep deprivation. Finally I examine the responses of P. cordiformis to video playback, testing the way in which motion and shape mediate predatory behaviour in P. cordiformis, and risk assessment in response to a sympatric predator (Arctocephalus forsteri). Pinnoctopus cordiformis responded well to acclimation, with little if any change in behaviour over the three day acclimation period, and minimal indication of stress (e.g., only one case of food rejection, and no changes in groom rates). Acclimation was not influenced by sex differences, or by differences in body weight or limb condition. Pinnoctopus cordiformis did not appear to possess homeostatic regulation of sleep behaviour following sleep deprivation, indicating that the variability in sleep and rest patterns seen in aquatic mammals and elsewhere also exists between octopuses of different species. Video playback of prey stimuli elicited context-relevant responses including changes in luring, peering and alertness as well as appearance characteristics, and this response was mediated by both prey motion and shape. Predator playback elicited semi-realistic responses including adjustments in alertness, flinching activity, and strong adjustments in rates of ventilation caused by behavioural freezing, as well as an alternate fight-flight response depending on video realism.