PLAY IN A CAPTIVE BREEDING COLONY OF HARBOR SEALS (PHOCA-VITULINA) - CONSTRAINED BY TIME OR BY ENERGY

The play of a breeding colony of captive harbour seals (Phoca vitulina ) was documented over a four-year period to identify changes associate d with seasonal variations in energy use, and to corroborate previous field studies which were restricted to observations at the hauling gro unds during breeding and moulting. Outside the breeding/moulting perio d, play was more frequent and in some animals average daily food intak e was higher. Thyroid hormones did not vary seasonally in any clear ma nner. The adults increased their daily activity markedly during the br eeding/moulting period. It is argued that these changes in play rate w ere a reflection of constraints on time rather than energy, since the animals played most when mass and fat were being accumulated for the w inter. Field observations were confirmed in the laboratory, showing mo st play to be solitary, with significant amounts of adult play which w as more stereotyped than that of younger seals. Behaviour in captivity was less ebullient and sometimes truncated in comparison to that seen in the wild; however, nine new types of play and a more elaborate rep ertoire of object play were seen in the laboratory, where seals could be observed throughout the year and underwater.