THE GROSS-ANATOMY, CELLULAR STRUCTURE, AND FATTY-ACID COMPOSITION OF ADIPOSE-TISSUE IN CAPTIVE POLAR BEARS (URSUS-MARITIMUS)

The gross anatomy, microscopic structure, and fatty acid composition o f adipose tissue in four elderly polar bears (Ursus maritimus), that h ad each been in captivity for more than 24 years, were compared with t hat of young wild specimens. Total dissections were performed on two s pecimens. In both, the proportion of adipose tissue in the body was si milar to that of younger wild bears, but the total adipocyte complemen t was smaller than that of the wild bears in one specimen, and within the normal range in the other. There was proportionately more intra-ab dominal adipose tissue, particularly in the inner ventral wall of abdo men depot, in which the number of adipocytes was substantially greater than expected. The fatty acid composition of the triacylglycerols dif fered substantially from that of the wild bears, reflecting their diet of fish, domesticated herbivores, bread, and fruit, but there were al so significant differences between cage-mates eating similar diets.