spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online May 21, 2007
Journal of Experimental Biology 210, 1960-1970 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.02767
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Yeates, L. C.
Right arrow Articles by Fink, T. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yeates, L. C.
Right arrow Articles by Fink, T. L.

Diving and foraging energetics of the smallest marine mammal, the sea otter (Enhydra lutris)

Laura C. Yeates*, Terrie M. Williams and Traci L. Fink

Department of Ecology and Evolutionary Biology, 100 Shaffer Road, University of California, Santa Cruz, CA 95060, USA

* Author for correspondence at present address: SPAWAR Systems Center San Diego, 53560 Hull Street Code 235, San Diego, CA 92152-6506, USA (e-mail: yeatesl{at}spawar.navy.mil)

Accepted 5 March 2007

As the smallest and one of the most recently evolved marine mammals, sea otters face physiological challenges rarely encountered by larger, more derived aquatic species. To examine the effect of these challenges on foraging costs and resultant daily energy budgets, we measured the energetics of resting, grooming, diving and foraging for adult, male sea otters. The energy expended for these different behaviors as determined from open flow respirometry was then standardized across activity budgets measured for wild sea otters to estimate field metabolic rates (FMR). We found that the metabolic rate of captive otters performing single dives ranging in duration from 40 to 192 s was 17.6±0.5 ml O2 kg–1 min–1 and only 1.3 times resting rates. This rate increased significantly if the animals foraged during submergence. The cost of a foraging dive for sea otters was nearly twice that predicted for phocid seals, which was attributed in part to elevated locomotor costs associated with buoyancy and swimming style. Our behavioral studies indicate that wild sea otters spend the greatest proportion of the day feeding and resting, with the largest daily energy expenditure (6.1±1.1 MJ day–1) associated with foraging. The resulting mean FMR for wild sea otters based on the energy expended for all behaviors was 15.7±2.7 MJ day–1 and matched predicted FMR values based upon a regression of known FMR values for other marine mammals across a range of body sizes. This was achieved by counterbalancing elevated foraging costs with prolonged periods of rest on the water surface.

Key words: energetics, sea otter, foraging, diving, behavior






© The Company of Biologists Ltd 2007