170 



NORTH AMERICAN FAUNA 74 



Fig. 105. Captive walrus in the New York Aquarium feeding on whole, soft-shelled 

 clams, Mya arenaria: (a) the clam is taken in the lips, (b) the shells are ejected after 

 removal of the siphon by suction, (c) the ejected shells are re-inspected tactually by 

 means of the vibrissae; (d) view of the remains, with two intact clams (upper left) for 

 comparison. (Photos by S. Dunton, N.Y. Zoological Society) 



obtained repeated readings of "-27 in. Hg" which he felt were conservative, 

 inasmuch as the animal was "still pulling a lot of air around the mouthpiece." 



That walruses of all ages in captivity suck up their food and any other small 

 objects in their pen, is well known to their keepers (see Reventlow 1951). Such 

 animals in captivity also have a reputation for using their remarkable vacuum 

 for removing paint and other coating from the walls of their tanks (G. C. Ray 

 and D. H. Brown, personal communication) and for toying with large, 

 noningestible objects. Hagenbeck (1963:25), in speaking of those under his care, 

 noted that "the outlet of their swimming pool (1.10 m deep) is closed with a 

 metal plug, weighing 5 lbs., and the walruses have no difficulty in sucking this 

 out when the basin is full of water." He, as well as Coats and Atz (1958) and 

 Ruempler (1976) also reported that their walruses, when given whole, large 

 herring, very neatly sucked off all of the flesh, leaving only the skeletons. 



