Autumn fat deposition and gross body composition in three species of Myotis

1. 1. Mid-August to mid-September fat indices for female Myotis lucifugus were 0·58–0·69 g fat/g lean dry wt. with constant gross body composition. 2. 2. During the same trime span, fat indices of female M. yumanensis showed a gradual significant increase from 0·30 to 0·87 with a concurrent significant increase in percent non-fat and percent water. 3. 3. In mid-September, fat indices of M. thysanodes increased significantly from 0·09 to 0·73, while gross body composition was unchanged. 4. 4. M. thysanodes body fat had a caloric content of 9·418±0·016 kgal/g. 5. 5. Fatty acid analysis revealed 72–81 per cent unsaturation with oleic acid being the most abundant. 6. 6. For each species, females contained more body fat than males, and adults were fatter than young of the year.