OLIVER ET AL.: WALRUS FEEDING IN BERING SEA 



E 

 o 



O 

 ro 



Mya pits x.s 



plan view 



e 



a 



30 cm 



Serripes pits x.s 



Macomo pits x.s. 



FIGURE 2. — Illustrations of the large Mya truncata and Macoma spp. pits, and the smaller pits created by excavating Serripes 



groenlandicus. 



Evidence for Single Diving Events 



Mya pits generally were found in distinct groups 

 with a distance of at least 5 m between patches of 

 pits. There was no significant difference between the 

 number of pits per patch or the area covered by a 

 group of pits when two similar dive sites were com- 

 pared from Cape Nome (Table 4). Patches included 

 from 1 to 20 pits, which may represent the activities 

 of a walrus during a single dive. 



We found one excellent record of the number of 

 clams taken in a single feeding event in a pit-furrow 



Table 4. — Number of Mya pits found per group and area of the 

 patches in two similar locations near Cape Nome. Means and 95% 

 confidence limits in N samples. 



Cape Nome-2 



Cape Nome-1 



Prob. 1 



Pits per patch 

 Patch area (m 2 ) 



15 

 15 



6.1+2.6 

 10.6±7.6 



12 

 12 



5.6±3.2 

 180±98 



P>0.3 

 P>0.2 



Probability of difference in r-test. 



system located off Cape Nome (Fig. 3). The pits or 

 shells of 19M. truncata and 15 S. groenlandicus were 

 located in this continuous pit-furrow. Unfortunately, 

 we could not survey the entire system because of a 



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