Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus).

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters (Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2-3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5 degrees C) than moderate (23 degrees C) ambient temperatures. Removal of 8 cm(2) of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm(2) had no effect. An 8-cm(2) fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.