Fat Deposition in Spitzbergen Ptarmigan (Lagopus mutus hyperboreus)

Fat depots and muscle lipids were measured in ptarmigan shot at Longyearbyen in fall and in spring. In the fall the ptarmigan weighed 740 g of which l00 g was dissectable fat and 11.5% of the pectoralis dry weight was lipid. In the spring the fat depots were almost absent and muscle lipid was halved. Neither Alaskan nor Scandinavian rock or willow ptarmigan show comparable fat depots, but the muscle lipid levels compare favourably with values obtained for Spitzbergen ptarmigan. Even larger fat depots were found in the Spitzbergen reindeer and fall fat deposition is most likely an important metabolic adaptation in high-arctic herbivores