THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 



55 



otter lived to the age of **14 years and 4 or 5 months" (Scheffer, 

 1958). 



The Senses 



The various senses are mentioned or discussed in context under 

 different subject headings in other parts of the text. A brief 

 summary of observations of the use of the senses is given below. 



SIGHT AND SMELL 



The sense of sight appears moderately well developed but, on 

 land at least, is less important than smell as a warning sense. The 

 following observation illustrates this: 



I approached a dispersed group of 25 otters sleeping on the rocks. The S. W. 

 breeze of ca. 4-6 knots was such that I could approach cross wind. I moved 

 quietly to within about 10 feet of a group of six sleeping animals and made a 

 noise to awaken them. The animals looked at me but were not alarmed. After 

 taking photos I made some quick movements and they became mildly alarmed 

 and went slowly to the water which was in a channel about 15 feet wide 

 among the rocks. Here they preened — not alarmed. Then they swam slowly 

 to a point directly down wind of me. As they got my scent, all dived in great 

 alarm and swam frantically away under water. 



One old male awoke of his own accord and walked leisurely over the rocks 

 on my upwind side. He was only 3 feet away. He looked at me with no 

 recognition — I moved slowly and took a picture, the click startled him but he 

 was not alarmed and ambled around behind me, to a point downwind of me. 

 When he caught my scent he took extreme alarm and scrambled frantically 

 over the rocks, dived into the water, and did not come up until 100 feet away. 

 (Field notes, 12 March 1962, East Cape, Amchitka Island, Alaska.) 



When otters feeding or resting in the water are approached by 

 a human observer and the wind is blowing from the observer to 

 the otters, they become restless. Feeding and resting animals rise 

 high in the water and sniff the air. Although there is no rapid 

 movements or indication of alarm, it is generally true that all 

 animals will leave the area within about 10 minutes after the ob- 

 server's arrival. In the same locations, when the wind blows from 

 the otters toward the observer, the otters remain unconcerned even 

 though the observer moves about on land in clear view. 



As mentioned under ''Food and Feeding Behavior," sight under 

 water may be useful in finding food. Gentry and Peterson (1967) 

 demonstrated that a sea otter was capable of quite a high degree of 

 accuracy in distinguishing, under water, the size of experimental 

 disks. 



