ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



139 



I found the stomachs of calves less than 1 month old to be either empty or 

 filled with milk. The St. Lawrence Islanders also stated that they never found 

 anything other than milk in the stomach of newborn calves taken during April to 

 June. Two of 60 hunters contacted stated that they occasionally had found bits of 

 solid food (invertebrates) in stomachs of 5- to 6-month-old calves taken in 

 November and December. From the infrequency of such reports, I judge that the 

 calves do not take solid foods ver\' often at that age. A calf born in captivity at 

 Marineland voluntarily began to take solids in small quantities when about 

 8 months old (T. Otten, personal communication). 



On one occasion in March, I watched about 20 calves (about 10 months old) 

 that were diving with their mothers while the latter apparently were feeding 

 (based on their repeated dives in the same location and their bringing up inver- 

 tebrates in their mouth) , but I was unable to determine whether the calves also 

 were feeding on benthos. In two of three 12- to 13-month-old animals, I found 

 only milk, but the third contained an operculum of Neptiinea sp. (a large 

 gastropod mollusk), along with some stones and gravel (Table 19). E. H. Miller 

 and B. Hines (personal communication) reported the presence of a calf about 13 

 months old at Round Island in 1972. That animal, unaccompanied by its 

 mother, was fat and seemed in normal health (Fig. 95), suggesting that it had 

 been feeding independendy. 



Table 19. Stomach 



contents of young w 



alruses less than 3 



years old. 







Number 



of stomachs 



containing 







Age 



Number 



Milk only 



Milk and 



Invertebrates 





(months) 



examined 



or empty 



invertebrates only 





Authority^ 



0-1 



10 



10 



0 



0 



M, U 





2-3 



> 3 



> 3 



0 



0 



F, M 





4-5 



3 



3 



0 



0 



C, M 





6-7 



>20 



>20 



few 



0 



G 





12-13 



3 



2 



0 



1 



U 





14-15 



9 



7 



0 



2 



B, C, 



M, N, U 



16-17 



10 



10 



0 



0 



C, L, 



M 



17-18 



<10 



most 



few 



few 



G 





22 



1 



0 



1 



0 



U 





24-27 



>11 



2 



1 



>8 



B, C, 



F. G. L. M, N, U 



'B = Brooks (1954). C = Chapskii (1936). F - Freiman (1941). G = Gambell Eskimos 

 (personal communication). L = Loughrev (1959), M = Mansfield (1958a), N = Nikulin 

 (1941). U = F. H. Fay (unpublished data). 



In seven out of nine animals that were 14 to 15 months old. the stomach 

 contained only milk or was empty. In the stomach of one of this age reported by 

 Brooks (1954:59), however, there were "stones and animal matter"; in the 

 stomach of another that I examined, there were about 10 kg of feet of the bivalve 

 Serripes groenlandicus. Because each of these latter two animals was alone, 

 rather than accompanied by an adult, the stomach contents may have been 

 atypical for animals of their age. Nevertheless, they indicated that some 



