THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 295 



otters were held frozen (at about -}-10° F.) for at least 24 hours. 

 Apparently all helminth parasites were killed by this treatment. 



A Soviet biologist (Shidlovskaya, 1947) states that fresh fish 

 "is always better than frozen fish." Our experience is not in 

 accord with this statement. During extended periods in captivity, 

 otters were regularly fed fish that had been frozen and health 

 remained excellent. 



FOOD QUANTITY REQUIRED 



During the period March 1956 through December 1957, records 

 of the food consumed by Susie, a captive female sea otter, were 

 kept on 602 days. Keeper Richard D. Clark used a 25-lb. capacity, 

 Chatillon, platform-spring scale to weigh all food to the nearest 

 14 lb. (occasionally to 14 lb.). The otter was fed three times daily 

 (morning, noon, and late afternoon). Food in excess of the otter's 

 daily consumption was offered. Before the morning feeding, the 

 pool was drained and all food scraps from the previous day were 

 removed and weighed. From these data the approximate weight 

 of the food consumed was calculated. A screen over the pool drain 

 minimized loss of remnant food scraps. The data from the daily 

 feeding record are summarized in table 61. 



The weight of this female (six weighings) averaged 39 lb. 

 (17.7 kg.). She consumed about (daily average, 1 year, 1957) 

 8.9 lb. (4.04 kg.) or about 23 percent of her body weight per day, 

 approximately 228 g. /day /kg. of body weight. The extremes, using 

 monthly averages were 24 percent (in February) and 20 percent 

 (in April) of body weight consumed per day. 



The actual daily consumption of food ranged from a minimum 

 of about 2 lb. (0.9 kg.) to 16 lb. (7.2 kg.). The range in amount 



Table 61. — Food consumption of a 39 lb. {17.7 kg.) sea otter (Susie) at the 



Seattle Zoo 



Kilograms of food 



Extremes of 



average 

 daily intake ^ 





Days 



Total 



Total 







- Average daily 



Observation 



data 



food 



food 



Maxi- 



Mini- 



intake entire 



period 



kept 



offered 



consumed 



mum 



mum 



period 



1 March- 















31 December 1956 2 



261 



1,587.3 



930.3 



4.17 



2.95 



3.58 



1 January- 















15 December 1957 » 



341 



2,129.6 



1,374.7 



4.31 



3.54 



4.04 



Total ( and mean ) 



602 



3,716.9 



2,305.0 



4.24 



3.24 



3.81 



1 The average daily intake during each month was computed. 



2 Except August when no data were kept. 



3 A second otter was placed in the enclosure at the end of this period. 



