The most immediate and detrimental effect of an oil spill on sea otters is fur contamination. The insulating properties of the pelage result primarily from the layer of air trapped between the hairs. Oil penetrates the fur, eliminates the air layer, and reduces the insulation of the pelage by 70% (Williams et al., 1988). To offset the increased heat loss and maintain a normal core body temperature, oiled otters must further increase their normally high metabolic rate to prevent hypothermia. Alternatively, they can reduce heat loss by leaving the water. However, hauling out on shore prevents the sea otter from foraging, and starvation occurs rapidly. In this chapter, we describe: 1) the physical properties that make sea otter fur an effective insulator in water, 2) the detrimental thermoregulatory effects of oiling, and 3) methods to restore the insulating quality of the fur through proper cleaning and care.
