Title
Sex-specific foraging strategies and resource partitioning in the southern elephant seal (Mirounga leonina)
Author(s)
Lewis R., O'Connell T.C., Lewis M., Campagna C., Hoelzel A.R.
Published
2006
Publisher
Proceedings of the Royal Society B: Biological Sciences
Abstract
The evolution of resource specializations is poorly understood, especially in marine systems. The southern elephant seal (Mirounga leonina) is the largest of the phocid seals, sexually dimorphic, and thought to prey predominantly on fish and squid. We collected vibrissae from male and female southern elephant seals, and assessed stable C and N isotope ratios along the length of the vibrissae. Given that whiskers grow slowly, this sampling strategy reflects any variation in feeding behaviour over a period of time. We found that isotopic variation among females was relatively small, and that the apparent prey choice and trophic level of females was different from that for males. Further, males showed a very broad range of trophic/prey choice positions, grouped into several clusters, and this included isotopic values too low to match a broad range of potential fish and cephalopod prey tested. One of these clusters overlapped with data for South American sea lions (Otaria flavescens), which were measured for comparison. Both male southern elephant seals and southern sea lions forage over the continental shelf, providing the potential for competition. We discuss the possibility that individual southern elephant seals are pursuing specialist foraging strategies to avoid competition, both with one another, and with the South American sea lions that breed nearby. © 2006 The Royal Society.
Keywords
carbon; isotope; nitrogen; carbon isotope ratio; cephalopod; continental shelf; foraging behavior; interspecific competition; niche partitioning; nitrogen isotope; pinniped; prey preference; sex-related difference; trophic level; animal experiment; animal tissue; article; cephalopod; controlled study; feeding behavior; female; fish; foraging behavior; male; nonhuman; prey; priority journal; seal; sex difference; squid; vibrissa; Animals; Carbon; Female; Male; Nitrogen; Periodicity; Predatory Behavior; Seals, Earless; Sex Characteristics; Sex Factors; Vibrissae; Cephalopoda; Mammalia; Mirounga leonina; Otaria byronia; Otariidae; Phocidae
Access Full Text
A full-text copy of this article may be available. Please email the WCS Library to request.
![]()
Back
PUB10801