Body Composition, Energy Content, and Lipid Cycles of Two Species of Pocket Gophers (Geomys Bursarius and Pappogeomys Castanops) in Kansas

Body composition, energy content, basic weight, and lipid cycles were determined for populations of the plains pocket gopher (Geomys bursarius) and the yellow-faced pocket gopher (Pappogeomys castanops) in Kansas. Lipid content calculated as a percentage of dry body weight varied from 11.35 to 32.20 per cent in G. bursarius and from 14.61 to 30.04 in P. castanops. Seasonal means for energy content ranged from 1.29 to 1.57 kcal/g live weight for G. bursarius and from 1.38 to 1.62 for P. castanops. Per cent ash and water varied from 17.55 to 18.64 and from 67.13 to 72.59, respectively. In both males and females of G. bursarius, basic weight increased from autumn until winter, whereas in males of P. castanops basic weight decreased from summer until winter but in females basic weight decreased only from autumn until winter. Values for per cent lipids dry body weight, per cent lipids live body weight, and kilocalories per gram biomass were significantly lower for subadult P. castanops than adult P. castanops during the summer but per cent water was significantly higher. Seasonal lipid cycles were similar in the two species, with the low in early or middle summer and the high in late winter or early spring. It is postulated that lipid cycles of pocket gophers are the result of energetically expensive activities associated with breeding and burrowing. Numerous ecological studies (Downhower and Hall, 1966; Ingles, 1952; Miller, 1964; Wilks, 1963) have been conducted on pocket gophers of the genera Geomys and Thomomys; however, little has been published on Pappogeomys, and no investigation of any of these genera has dealt with lipid cycles. Fleharty et al. (1973) summarized data on body composition, lipid cycles, and lipid deposition of four species of rodents in Kansas and attributed differences in lipid cycles among those rodents to historic and evolutionary factors. The purposes of this study were to elucidate lipid cycles and body composition for the two species of pock