picture courtesy of Jimmy's Sea Otter page
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picture courtesy of Jimmy's Sea Otter page |
| One of Enhydra lutris's thermoregulatory adaptations is a high metabolism. Sea otters have a basal metabolic rate of .72 cm^2 O2 (ghr)-1 in a thermal neutral zone of 20-33 degrees Celsius in water. Their resting metabolic rate is 2.4 times that of terrestrial animals the same size and 1.8 times that of other Mustelids. (Davis, et.al, 1988) Sea otter's metabolic capacity can endure cold stress up to -19C. (Morrison, et.al, 1974) |
| In order to maintain their high metabolism, sea otters must consume 20% of their body weight in food each day. The sea otter is considered a "carnivorous grazer" (Morrison, et.al,1974) whose diet includes clams, crabs, urchins and mussels. (Bodkin and Ballachey, 1997) One disadvantage of sea otter's high metabolisms is that they have few fat reserves. So, in times of reduced food reserves or metabolic stress, they may not be able to intake enough food to maintain their body temperature. Without caloric reserves, their metabolism decreases along with their body temperature and they become hypothermic. This can occur as a result of fur contamination due to an oil spill. |
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Sea otters have been found to also manipulate the metabolic "bulge" which
occurs after an organism eats. This increase in resting metabolism
is known as the specific dynamic action (SDA). Sea otters have developed
the ability to use this increase in metabolism to aid in thermoregulation.
Sea otters typically forage for food three times a day and then spend four to six hours resting afterward. Their SDA usually lasts for 4.2-5.3 hours after a meal which correlates to their resting period. Thus, it was concluded that the increase in metabolism due to SDA allows them to rest without experiencing a decrease in body temperature. This increase in metabolism is not totally sufficient in maintaining body temperature, so wild sea otters will interrupt their rest with bouts of activity. (Costa and Kooyman, 1983) |
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other physiological adaptations oil spills and sea otters references |