| Autor: |
Rutishauser, Matthew R.1 rutishauser@biology.ucsc.edu, Costa, Daniel P.1, Goebel, Michael E.2, Williams, Terrie M.1 |
| Předmět: |
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| Zdroj: |
Physiological & Biochemical Zoology. Jul/Aug2004, Vol. 77 Issue 4, p669-681. 13p. |
| Abstrakt: |
in comparison with other homeotherms, young recently weaned marine mammals in high latitudes face exceptional energetic demands when foraging and thermo regulating. Lipids are an important source of energy and a major component of insulation that allows them to meet these demands. To examine the role of lipid stores in a high-latitude pinniped, we measured the body composition and thermoregulatory capabilities of Antarctic fur seal (Arctocephalus gazella) pups and yearlings by using flow-through respirometry and hydrogen isotope dilution. From these data, we constructed a model to examine the importance of postweaning fasting capability in free-ranging young fur seals. Resting metabolic rates were different for pups and yearlings measured in 0.6°C water, 10.3°C water, and ambient air; however, mass and percent lipid as covariates accounted for the different metabolic responses in pups and year- lings for all treatments. The estimated lower critical temperature for combined pups and yearlings was 14.4°C, 10°-15°C above water temperatures normally experienced by Antarctic fur seals. Modeling predicted that a weaned fur seal pup would survive at sea from 9.8 to 36.2 d before succumbing to starvation. The most likely maximum travel distance within this time constraint suggests that food resources close to the natal rookery are important to first-year survival for this species. [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
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