The Effects of Environmental Enrichment on the Ability of Octopus rubescens to Learn Novel Behavior

Abstract

Environmental enrichment provides captive animals complex inanimate and social stimuli in order to promote the animals' welfare and natural behavior. The application of enrichment has become commonplace for many animals but has only recently been applied to in vertebrates. This may be due to a lack of empirical evidence demonstrating the benefits of enrichment. The effect of environmental enrichment on the ability of Octopus rubescens to learn novel behavior was examined by presenting four octopuses a vial containing a food reward and recording their ability to open it before and after a 30-day period in one of two environmental treatments. Two octopuses were put into an impoverished treatment, which consisted of a bare tank with a black veil preventing external visual stimulation and a diet of frozen fish. Two octopuses were placed into an enriched treatment, which provided a semi-natural environment and the opportunity to perform natural behavior such as hunting live food. The ability of 0. rubescens to learn novel behavior was not aided by enrichment; nor did impoverishment outright impair the learning of a novel behavior. Though exposure to different environments may affect learning, our limited sample size and the variable behavior of the subjects prevented any firm conclusions. However we maintain that enrichment should be included in Octopus animal husbandry until empirical testing quantitatively demonstrates that it is not beneficial. Further studies would benefit from larger sample sizes and examining other ways of gauging enrichment that do not rely solely on food puzzles.