Trade-offs between energy maximization and parental care in a central place forager, the sea otter

Behavioral Ecology
By: , and 

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Abstract

Between 1999 and 2014, 126 archival time–depth recorders (TDRs) were used to examine the foraging behavior of southern sea otters (Enhydra lutris nereis) off the coast of California, in both resource-abundant (recently occupied, low sea otter density) and resource-limited (long-occupied, high sea otter density) locations. Following predictions of foraging theory, sea otters generally behaved as energy rate maximizers. Males and females without pups employed similar foraging strategies to optimize rates of energy intake in resource-limited habitats, with some exceptions. Both groups increased overall foraging effort and made deeper, longer and more energetically costly dives as resources became limited, but males were more likely than females without pups to utilize extreme dive profiles. In contrast, females caring for young pups (≤10 weeks) prioritized parental care over energy optimization. The relative importance of parental care versus energy optimization for adult females with pups appeared to reflect developmental changes as dependent young matured. Indeed, contrary to females during the initial stages of lactation, females with large pups approaching weaning once again prioritized optimizing energy intake. The increasing prioritization of energy optimization over the course of lactation was possible due to the physiological development of pups and likely driven by the energetic deficit incurred by females early in lactation. Our results suggest that regardless of resource availability, females at the end of lactation approach a species-specific ceiling for percent time foraging and that reproductive females in the central portion of the current southern sea otter range are disproportionately affected by resource limitation.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Trade-offs between energy maximization and parental care in a central place forager, the sea otter
Series title Behavioral Ecology
DOI 10.1093/beheco/arw089
Volume 27
Issue 5
Year Published 2016
Language English
Publisher Oxford Journals
Contributing office(s) Western Ecological Research Center
Description 15 p.
First page 1552
Last page 1566
Online Only (Y/N) N
Additional Online Files (Y/N) N