154 



NORTH AMERICAN FAUNA 74 



Seasonal and Regional Diets 



The walrus population occupies specific parts of the continental shelf of the 

 Bering Sea in winter and mostly moves to different parts of that and the Chukchi 

 shelf in summer. Since the benthic faunas of those areas are not the same 

 (Neiman 1960; Zenkevich 1963; Stoker 1978), the feeding habits of the walruses 

 using them probably differ correspondingly. The available data on seasonal and 

 regional feeding habits suggest such differences. 



Winter: St. Lawrence concentration area. — Stomach contents have been 

 examined from only two walruses taken in the St. Lawrence concentration area 

 in winter (January 1957 and February 1970). Predominant in abundance and 

 volume in these were siphons of Mya sp. and whole specimens of Pelonaia corrii- 

 gata. Lesser amounts of large gastropods (feet only), feet and siphons of Serripes 

 groenlandicm and Mya triincata, respectively, and a few small crangonid shrimps, 

 gammarid amphipods, and holothurians also were included. On the ice beside 

 several breathing holes used by walruses in March 1972, S. W. Stoker and I 

 found remains of Pagurm sp., Macoma sp., and Musculus sp., an intact 

 specimen of Neptunea heros, and fragments of unidentified gastropod egg cases. 

 In walrus feces from several haulout areas, we identified the undigested remains 

 of Echiurus echiurus, Priapuhis caiidatus, Nucula sp., Mya truncata, Neptunea 

 sp., Natica sp., Polinices sp., Chionoecetes opilio, and Pelonaia corrugata. 



Winter: Bristol Bay -Prihilof concentration area.— The food items predomi- 

 nant in numbers and volume in the stomachs of 21 specimens taken about 

 220 km east of the Pribilof Islands in March and April 1976 were feet of Serripes 

 groenlandicm and Clinocardium sp. and whole brachyuran crabs of the genus 

 Chionoecetes. Smaller amounts of Neptunea and Buccinum spp., Mya truncata, 

 Hyas coarctatus, and an unidentified tunicate also were present. In walrus feces 

 on the ice, I found abundant remains of Neptunea, Buccinum, Polinices, and 

 Chionoecetes. 



Two specimens taken just south of the mouth of Kuskokwim Bay in January 

 1970 contained principally feet of Clinocardium sp., Neptunea sp., and 

 Buccinum sp. The only other items in these stomachs were a few tunicates, prob- 

 ably of the genus Tethyum. 



Tikhomirov (1964:283) reported that the stomachs of 50 walruses taken to the 

 south of Nunivak Island in March 1962 contained principally "shrimps, crabs 

 (among which were a few king crabs [Paralithodes camtschatica]) , and in lesser 

 amounts mollusks." Further details were not given, and because this report 

 differs so markedly from all others, I suspect that it is inaccurate. 



Spring: St. Lawrence Island-Bering Strait region. — The stomach contents of 

 19 walruses taken by Eskimos from Gambell in the waters off the western end of 

 St. Lawrence Island in April and May 1975 contained a predominance of siphons 

 of Mya truncata, Hiatella arctica, and Mya spp. and feet of Serripes groen- 

 landicm. Of secondary importance in numbers and volume were Nephthys, 

 Neptunea, Buccinum, Hyas coarctatus, and Thyonidium commune. 



In 14 specimens taken to the north and northeast of Savoonga in May and June 

 1974 and 1975, the principal food items were siphons oiMya and feet of Serripes. 

 Secondary to these in volume were feet of Clinocardium sp. and whole specimens 

 of Thyonidium commune. The stomach of one additional specimen from this 



