Chap. XVII. 



MEANS OF DEFENCE. 



2C3 



parts developed solely as a means of defence against 

 the attacks of other males. Some kinds of deer use, 

 as we have seen, the upper branches of their horns 

 cliiefly or exclusively for defending themselves ; and 

 the Oryx antelope, as I am informed by Mr. Bartlett, 

 fences most skilfully with his long, gently curved horns ; 

 but these are likewise used as origans of offence. Ehi- 

 noceroses, as the same observer remarks, in fi"htinfi" 

 parry each other's sidelong blows with their horns, 

 which loudly clatter together, as do the tusks of boars. 

 Although wild boars tight desperately together, they 

 seldom, according to Brehm, receive fatal blows, as 

 these fail on each other's tusks, or on the layer of 

 gristly skin covering the shoulder, which the German 

 hunters call the shield ; and here we have a part speci- 

 ally modified for defence. With boars in the prime 

 of life (see tig. 63) the 

 tusks in the lower jaw- 

 are used for figh ting- 

 but they become in 

 old au'e, as Brehm 

 states, so much curved 

 inwards and upwards, 

 over the snout, that 

 they can no longer be 

 thus used. They may, 

 however, still continue 

 to serve, and even in 

 a still more effective 

 manner, as a means of defence. In comnensation for 

 the loss of the lower tusks as weapons of offence, those 

 in the upper jaw, which always project a little later- 

 ally, increase so much in length during old age, and 

 curve so much upwards, that they can be used as a 

 means of attack. Nevertheless an old boar is not so 



Fig. 63. 



Head of common wild boar, in prime 

 of lite (_froin Brehm). 



