264 



SEXUAL selection: mammals. 



Part IL 



daiigeroiis to inan as one at the age of six or seven 

 years.^^ 



In the full-grown male Babirusa pig of Celebes 

 (fig. 64), the lower tusks are formidable weapons, like 

 those of the European boar in the prime of life, whilst 

 the upper tusks are so long and have their points so 

 much curled inwards, sometimes even touchiiio; the 



Fig. (31. Skull of the Babirusa Pig (from "Wallace's 'Malay Archipelago ) 



forehead, that they are utterly useless as weapons of 

 attack. They more nearly resemble horns than teeth, 

 and are so manifestly useless as teeth that the animal 

 was formerly supposed to rest his head by hooking them 

 on to a branch. Their convex surfaces would, however, 



^^ Biebm, 'Tliierleben,' B. ii. .s. 720 732. 



