252 ADVENTURES IN THE NORTHERN SEAS. 



easily fancy that in the struggle for existence per- 

 petually going on, this bear — or whatever he was — 

 may have been compelled to take to the sea-shore 

 and prey upon shell-fish among other things. At 

 first he would only go into shallow water, but he 

 would become emboldened, by success and habit, to 

 go deeper and deeper ; even in the lifetime of one 

 individual this would happen, and he would ac- 

 quire the habit of digging shells up with his feet 

 or his teeth — at first probably with his feet, but 

 latterly, when he came to picking shells in a foot or 

 two of water, he would require to see what he was 

 about, and he would use his teeth. Natural selec- 

 tion would now come into play, and as those an- 

 imals which had the best and longest teeth would 

 succeed best, so they would have the best chance 

 of transmitting these peculiarities to their descend- 

 ants. The tusks of the walrus are not, as I men- 

 tioned before, a pair of extra teeth, but merely an 

 enlargement or extraordinary development of the 

 eye-teeth, and I think it is easy to conceive that 

 any large carnivorous animal, driven by necessity 

 to subsist on shell-fish under water, would, in a few 

 thousands of generations, acquire such tusks. 



Also, he would soon learn to dive,* and to hold 

 his breath under water, and from generation to 

 generation he would be able to stay longer below. 

 As he would have very little use for his legs, they 



* I stated, ante, that we had seen the white bear dive for a 

 short distance just like a walrus. 



