Oxygen consumption, thermoregulation, and the effect of fur oiling and washing on the sea otter, Enhydra lutris

The relative importance of a water-repellent fur was assessed by changes in oxygen consumption [Formula: see text] and in body and subcutaneous temperatures before and after oiling and washing in 15 °C water. In addition, changes in posture and [Formula: see text] in five sea otters were measured while immersed in water from 5 to 30 °C. Measurements were made in an enclosed water bath with Vo 2 determined by open-flow respirometry. Core body and subcutaneous temperatures were telemetered. Resting [Formula: see text] was 11.7 mL O 2 ∙kg −1 ∙min −1 and did not significantly increase with decreasing temperature. Average and active [Formula: see text] increased with decreasing temperature. Average [Formula: see text] (16.0 mL O 2 ∙kg −1 ∙min −1 ) increased 41% (22.0 mL O 2 ∙kg −1 ∙min −1 ) after oiling 20% of the total fur surface and more than doubled (32.6 mL O 2 ∙kg −1 ∙min −1 ) after washing. Oiling and washing reduced the fur's insulating quality. The result was an energetic liability, since the average maintenance [Formula: see text] doubled in 15 °C water; this temperature is above typical water temperatures for this species, which range from 0 °C (Alaska) to 12 °C (California). Average [Formula: see text] returned to control levels after a minimum of 8 days.