The high cost of reproduction in sea otters necessitates unique physiological adaptations
Abstract
Superimposed on inherently high basal metabolic demands, the additional energetic requirements of reproduction can push female sea otters beyond physiological limits. Indeed, the resulting energy imbalance contributes to disproportionately high rates of mortality at the end of lactation in this species. To examine and quantify metabolic changes associated with reproduction, we measured the resting metabolic rate (RMR) of a female sea otter across gestation, lactation and non-reproductive periods. Concurrently, measurements were made on a non-breeding control female. Our results suggest that RMR declines during gestation. Conversely, RMR increases during lactation, reaches a peak at 3–4 months postpartum, and remains elevated until weaning. Combining these direct measurements with published data, we found the cost of pup rearing to be significantly higher than previously estimated. High baseline energy demands and limited energy reserves, combined with significant lactation and pup rearing costs, appear to necessitate metabolic and thermal lability during key reproductive stages.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2016
- Source ID
- 10.1242/jeb.138891
Entities
People
- Beau Richter
- Nicole M Thometz
- Terrie M. Williams
- Traci L. Kendall
Organizations
- Monterey Bay Aquarium
- National Science Foundation
- Office of Naval Research
- University of California, Santa Cruz