The structure of the sea otter coat has been investigated, but the vitally, important relationships of coat structure and physiology to environmental variables are poorly known. Water temperature is the most important external influence, but air temperature, humidity and water depth play definite roles in the maintenance of the otter coat. It can be seen that densities of wild sea otters typically are high in habitat areas in which these environmental factors are favorably balanced. In the wild sea otter populations can be found in areas where these environmental factors are in a suitable balance for the animals' survival.

Captive sea otters have been studied in 19 aquaria. Opportunities for input on facility design have permitted additional evaluation of environmental variables. Requirements for survival have been consistent in all captive situations. The volume of the air space above the holding pool plays a part in coat health.

An understanding of the coat needs provides a program for coat recovery as is often needed after long transports or following the insult of spilled oil or other factors; i.e. heat, humidity, restriction of physical activity. The 1989 Exxon Valdez oil disaster provided a stage for the implementation and examination of this understanding.