214 



NORTH AMERICAN FAUNA 74 



The percentage of cal\'es that survive through the first year is unknown. 

 Probably a few are taken by predators in summer and autumn; apparently a few 

 also die on the autumn hauling grounds from being trampled by adults (see 

 Intraspecific Tramnatization) . There are no records of calves dying during the 

 winter months or of any moribund animals at that time. At 1 year of age, during 

 the northward migration, some youngsters become separated from their parents, 

 and most of these young probably perish. Only a few of them seem to be capable 

 of obtaining their own food, hence of surviving for a time. 



Predatioii 



The Pacific walrus is one of the largest and most powerful inhabitants of the 

 Bering and Chukchi seas. As such, it is subject to predation by only a few known 

 or potential enemies: the polar bear {Ursus maritirnus). the killer whale [Orcinm 

 orca), and man. 



Polar Bear 



The polar bear preys mainly on ringed seals and bearded seals throughout its 

 range (Freuchen 1935; Pedersen 1957: L0n0 1970; Stirling and Archibald 1977), 

 but it is believed to take young walruses occasionally (Parovschikov 1964 in L0n0 

 1970). I know of no confirmed records of predation on walruses. In most 

 instances where bears had eaten walrus flesh, the walruses were known or 

 suspected to have been carrion. Novikov (1962 in Nyholm 1975) reported that 

 H'^c of the polar bear stomachs that he examined near Franz Josef Land 

 contained parts of walruses. Nansen (1926 in Mohr 1952) obser\-ed polar bears 

 feeding on the flensed carcass of an adult walrus, and he found another carcass of 

 an adult with skin intact that the bears apparently had inspected but were 

 unable to tear apart. Manning (1961) mentioned that Eskimos found eight bears 

 feeding on the carcass of a walrus at East Bay. Southampton Island, citing this as 

 an example of the bears feeding on carrion. I have seen several dismembered 

 carcasses of adult walruses on the Punuk Islands that had been torn apart and fed 

 on by bears. L0n0 (1970) reported that polar bears in the Svalbard area eat 

 walrus carcasses when they are available, 



I found parts of the hind flippers of a young walrus in the stomach of a 2- to 

 3-year-old bear killed near Gambell in January- 1957 and pieces of skin and hind 

 flipper from a walrus calf in another from the same locality in May 1966. The 

 Eskimos felt that the bears probably had fed on those walruses as carrion, since 

 several walruses had been shot there not long before the bears were taken. 



The best evidence known to me of attempted predation by polar bears on 

 walruses is in three anecdotal accounts b\' So\ iet biologists. Because these are not 

 generally available to English-speaking mammalogists. I quote them here, in 

 translation. 



In August 1935. in Long Strait, we obsen-ed a polar bear tr>1ng to capture a 

 young walrus. We quote the diary: "At 1:00 pm . . , one of the members of the 

 crew noticed a polar bear approaching a walrus herd \\ hich was spread along the 

 edge of the ice for 250 to 300 m. The ice where the walruses were K ing was about 

 80 to 90*^0 occupied. The animals were in groups of from 15 to 20 up to 300 

 indi\iduals per ice floe, and the total number in the herd amounted to se\'eral 



