Oxygen Consumption of the Eurasian OtterLutra lutrain Relation to Water Temperature

Abstract
Oxygen consumption ( ) was measured in three captive Eurasian otters (Lutra lutra L.) at rest out of water and at rest and at different levels of activity in water of different temperatures. Irrespective of behavior, variation in water temperature ( ; °C) accounted for 55% of the variation in (mL O₂ [kg · min]⁻¹): . Behavior (resting, swimming quietly, or vigorous activity) explained an additional 14% of variation. Behavior was itself dependent on temperature: activity increased when water temperature decreased. Differences in between individual otters could be explained almost entirely in terms of behavior. We conclude that the metabolic rate of otters is strongly affected by water temperature. This has implications for animals foraging for different lengths of time at varying prey densities. The resting metabolic rate (RMR) in air was 3.2 W · kg⁻¹ (9.50 mL O₂ [kg ·min]⁻¹), which is high for mammals of this size (as in other mustelids) but which is somewhat lower than that for the sea otter.