406 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1958 
mately 10 pounds of filleted fish, octopus, and clams each day. The 
male weighed 64 pounds and ate about 15 pounds daily. ‘Thus, food 
intake amounts to about one-quarter of the body weight for each 
animal daily. Sea otters are often temperamental and will suddenly 
refuse to eat one kind of food which previously was preferred, while 
eating ravenously something entirely different. Dried or canned 
foods have been consistently rejected. One day, however, a zoo of- 
ficial told a visitor, preparing to toss a slice of bread to the sea otters, 
not to do it because the animals would not eat bread. The visitor 
disregarded instructions and, surprisingly, the otter ate the bread. 
The use of a rock, held on the chest of an otter, as a base against 
which to break the hard shells of mollusks, has often been described. 
When rocks and clams were placed in our captive’s pool, she gathered 
them from the bottom and, holding the clams between her forepaws, 
banged them against the rock resting on her chest until the shells broke, 
thus confirming at close range what had previously been observed only 
at a distance. 
The manual dexterity of the sea otter is well illustrated by the unique 
habit described above, but we found our captives ingenious in other 
respects. The drain in the zoo pool was covered by metal mesh which 
fitted snugly in place. This the otter promptly removed when she 
entered the pool. Apparently the dark hole beneath fascinated her. 
Since food scraps plugged the open drain, her keeper secured a band 
of strap iron over the mesh with a bolt that projected above it. Un- 
daunted, the sea otter pounded the bolt with a rock until she succeeded 
in dislodging it. Rocks have now been removed from the pool, for in 
addition to attacking the drain she whiled away idle hours by pound- 
ing the edges of the pool until the cement was considerably damaged. 
The problem of adjusting sea otters to captivity so that they may be 
successfully transplanted is a challenging one and we still face many 
difficulties. Captive animals, when held in small cages and deprived 
of free access to water, often die of enteritis, pneumonia, or infections 
of the extremities. The difficulty of keeping their soft fur clean and in 
waterproof condition is complicated by the fact that they like to eat 
while lying on their backs and that their natural food contains an 
abundance of slimy fluid. Unless adequate facilities are provided 
for washing, their fur quickly becomes matted with foreign matter. 
The animals soon become wet to the skin, chilling results, and, after 
several hours of distress, death usually follows. After traveling by 
air in cramped cages the two otters brought to the Seattle zoo required 
a week of painstaking care before their fur regained its waterproof 
insulating qualities. Frequent indoor warm-water baths followed by 
periods of drying in heaps of shredded paper were necessary to prevent 
chilling. Doses of antibiotics during this critical period prevented 
the usual infections. | 
