FOOD AND FEEDING BEHAVIOR 



In this section, methods of food gathering and consumption, the 

 kinds and quantities of foods eaten, and the food requirements of 

 sea otters in the wild and in captivity will be discussed. This 

 information was gathered by means of field observation, quanti- 

 tative and qualitative studies of stomachs and feces, and data 

 gathered from otters held on Amchitka Island, the Woodland Park 

 Zoo, Seattle, and the Tacoma Aquarium. 



The amount of food required by the sea otter is greater than 

 that of most animals of comparable size. The sea otter stores 

 body fat but it does not accumulate fat in quantities comparable 

 to the blubber stored by most marine mammals. Because it lacks 

 an insulating blubber layer, the sea otter is dependent for warmth 

 in its chilly habitat upon its fur and upon the rapid metabolic 

 use of energy from food. Passage of food through the gastrointes- 

 tinal tract is rapid. Food marked with red dye passed through 

 an otter in about 3 hours (Dr. James A. Mattison, personal 

 communication). 



Periods of fasting which are characteristic of other marine 

 mammals, such as certain cetaceans and pinnipeds, would prove 

 fatal to the sea otter. Its vitality is maintained by a relatively high 

 and constant consumption of food. 



Studies comparable to ours in Alaska were conducted in the 

 Kuril Islands by Soviet biologists Nikolaev and Skalkin (1963) 

 and Nikolaev (1965b), 



Feeding location 



Sea otters habitually gather their food from the bottom or near 

 it in salt water ranging in depth from a few feet, in the intertidal 

 or littoral zone, to about 20 fathoms (40 m.). This is the greatest 

 depth from which we took an otter having food in its stomach. 

 The majority of otters feed within about one-half mile of shore. In 

 certain areas, particularly off the north shore of Unimak Island 

 in the Bering Sea, where shallow water extends far from shore, 

 they commonly range 3 to 10 miles offshore and one was seen in 

 this area about 17 miles from shore in water about 30 fathoms 

 (56 m.) deep (see table 10). 



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