A Comparison of Milk Composition in Myotis lucifugus and Eptesicus fuscus (Chiroptera: Vespertilionidae)

Abstract

Milk composition in two species of insectivorous bats (Myotis lucifugus and Eptesicus fuscus) was determined. No significant differences in fat, lactose, protein, or energy content were evident during the lactation period for M. lucifugus. The percentage of fat, lactose, and protein averaged 13.5, 3.3, 7.4, respectively, for M. lucifugus, and 16.4, 2.5, 6.2, respectively, for E. fuscus. Energy content of milk averaged 7.32 kJ/g for M. lucifugus and 8.37 kJ/g for E. fuscus. The percentage of lactose in milk from M. lucifugus was significantly greater than in E. fuscus, but there were no significant interspecific differences in percentages of fat or protein. The two species also differed significantly in content of five out of nine fatty acids.