70 SEXUAL DIMORPHISM 



can affect the voice, unless the snorting or gargling sound is 

 produced by the nose itself, and on this point the witnesses 

 give us no information. It is clear, I think, that the male 

 sea elephant does innate his nasal cavities when angry and 

 when fighting with rivals, and this inflation, with the 

 muscular movements and contractions associated with it, 

 constitutes the mechanical cause which, according to my 

 views, has in course of time produced the hypertrophy. But 

 it is by no means clear what is the object of the inflation. 

 It may be merely the result of emotional excitement, and 

 may be of no real use to the animal at all ; the jealousy and 

 rage of the creature must, as in other animals, find vent 

 somehow, and as seals, when they come to the surface of the 

 water, expire violently through the nose, snorting or dis- 

 tension of the nose may be to them the most natural way of 

 expressing their feelings. On the other hand, it might be 

 supposed that the enlarged and distended nasal region served 

 to protect the animal's head from its adversaries' attacks. 

 If this were the case we should expect to find the proboscis 

 lacerated with the adversaries' teeth, and we are not told that 

 this is the case : nothing at present known suggests that the 

 animal inflates his trunk for the purpose of defence, except 

 that, according to Moseley, the animal cannot be stunned by 

 blows on the snout as other seals can. Moseley says that 

 this is due to a bony crest on the skull and the strength of 

 the bones about the nostrils. 



In the Bladder -nosed Seal, Cystophora cristata, which 

 lives on the ice-fields of the North Atlantic, the peculiarity 

 of the mature male is also connected with the nose, but is of 

 a different character. The nose, instead of being elongated, is 

 dilated at the base on the dorsal side, so that its walls here 

 have been modified into a bladder which can be inflated 

 until it is as large as the head. The voice of these animals 

 is also very loud and is uplifted during their combats, when 



