photo courtesy of Jimmy Hu

         Sea otter's primary environment is marine.  This effects their thermoregulation because water has a heat conductivity gradient which is 25-100 times that of air. (Davis, et.al, 1988)  Conduction is the transfer of heat from a warmer body to a cooler one.  The conduction gradient refers to how easily heat flow into or out of a given material. (Schmidt-Nielson, 1998)  Fur and air have comparable thermal conductivities, thus fur is usually a fairly good terrestrial insulator.  (Schmidt-Nielson, 1998)  However, fur itself cannot compensate for the high conductivity of water.  Thus, in cold water environments, heat flows from an animals warm skin to the water fairly easily.  The animal must then compensate for the loss of body heat.

        The combination of living in a marine environment, a cold environment, being homeotherms and having a relatively small body mass makes thermoregulation an important process for sea otters. (Davis, et.al, 1988) 

        Sea otters are unique compared to other marine homeotherms because they do not have a layer of blubber for insulation.  They are also the smallest of the marine mammals.  Thus, their insulative adaptations are fairly unique.  They utilize a combination of a high metabolism, thick fur coat, behavioral adaptations and other physiological adaptations.