Meeting Abstract

P2.26  Wednesday, Jan. 5  Annual changes in activity budgets, body composition, and serum leptin of golden-mantled ground squirrels OSTROM, CE*; HEALY, JE; FLORANT, GL; Colorado State University, Fort Collins ceostrom@gmail.com

The golden-mantled ground squirrel (GMGS, C. lateralis) is a common Colorado hibernator. They have a robust annual cycle of body mass gain and loss, driven primarily by food intake. These animals are hyperphagic and obese in the autumn, but are aphagic in winter. The annual behavioral cycle of GMGS is of interest because activity levels can help determine energy expenditure with respect to seasonal changes. We trapped 14 GMGS and kept them in natural conditions in the laboratory (temperature and photoperiod changed in accordance with our latitude). We measured body composition and serum leptin concentrations once a month from June-March of 6 GMGS. We video-recorded the total activity of 8 other GMGS over a 24hr period once every month from September-January. We retained 4 of 8 GMGS for further behavioral study from February-August. We recorded the amount of time each animal spent performing behaviors (nesting, grooming, feeding, and random activity). Body mass increased from June-August in preparation for hibernation; from December-February, body mass gradually decreased. Fat mass changed proportionally to body mass. Generally, leptin increased with an increase in body mass and stabilizes at a lower concentration during the active months. We hypothesized that behaviors vital for hibernation preparation, such as feeding and nesting, would increase between August and October. By November we expected almost all activity to cease as GMGS started to undergo torpor. We expected to see a major increase in activity in April as GMGS began to arouse from hibernation. Correlating these animals’ annual behavioral patterns with changes in hormones, such as leptin, and body composition can provide a comprehensive profile of the annual cycle of a hibernator.