The behaviour of octopuis vulgaris Lam. in its natural habitat : a pilot study

Abstract

It was shown that useful results on octopus behavior can be produced by a sampling type programme of diving. In an area of approximately 70,000 sq . ft., of average depth 10- 15 ft. and with varied ecology, animals were observed in 37 different positions, seven of which were occupied for at least four consecutive days and therefore considered permanent, 13 were occupied on at least two days while the rest were temporary homes in which animals were observed once only. The main types of home are described. The distribution of the homes did not correlate obviously with the ecology, but homes were often very close together. A graph based on hourly observations of presence of animals in known homes shows high activity at night and in the morning but little towards dawn and dusk. Reasons for this are discussed and two types of movement (long and short-term) are postulated. Marking by sub-cutaneous injection of dye proved feasible but not entirely satisfactory. Observations of moving animals were made as the opportunity arose but little was gained by continuous watches of animals in their homes. No reproductive or brooding behavior was observed possibly because the site was too shallow. Food species were mainly crabs (especially Xantho and Pisa tetradon) and lamellibranchs, including Pinna; there was no evidence that fish was eaten.