Energetics of lactation in Peromyscus maniculatus

Abstract

Examination of female weights, offspring weights, and food intake during lactation indicated that Peromyscus maniculatus maniculatus support offspring by increasing food ingestion. Total caloric requirements over 21 days of lactation increased with increasing litter size and ranged from 576 kcal for a single litter of three to an average of 892 kcal for three litters of seven. Energy requirements attributed to offspring per se ranged from 253 kcal for a single litter of three to 548 kcal for litters of seven. An increased energy requirement of 134% of nonbreeding requirement for a modal litter of five was similar to that reported for several other small mammals.