70 



NORTH AMERICAN FAUNA 74 



Fig. 47. Differential abrasion of mystacial vibrissae of Pacific walruses, in relation to 

 their location on the snout: left, median sagittal section, with dorsal edge of snout at top; 

 right, oblique anterodorsal view, upper right quadrant. (Photos by G. C. Kelley and 

 F. H. Fay) 



She recognized that long vibrissae would be more of a hindrance than an aid to 

 the walrus, due to obstruction of the oral passageway. She concluded that their 

 main functions were sensory and that they were used for expressing changes of 

 mood. Howell (1930:77) stated that the walrus forces food into its mouth by 

 "medial contraction" of the rostral pad, and that a captive walrus was said to 

 have used its vibrissae to tear the flesh from a dead seal. Sokolowsky (1908) and 

 Nikulin (1941) indicated their belief that the mustache is used as a "broom" to 

 sweep together the food unearthed by the tusks. Brooks (1954:24) believed that 

 the pad and vibrissae performed both motor and sensory functions during 

 feeding, "... serving to sort out clams and like food from the muck stirred up 

 by the tusks." Social functions of the vibrissae for expressing threat and 

 submission, were described by Miller (1975i>). 



