Chapt. xv. The Otter hunts by scent. 191 



The otter picks up and follows the scent of a fish 

 under water, just as a dog does that of game on land. 

 You may think a fresh live fish has little or no odour. 

 Perhaps not to man, and you may be surprised at a scent 

 being left in water. But water retains a scent well, as 

 may be seen from dogs readily recognizing the scent of 

 deer, and following it across a stream. And as to the 

 powerfulness of different smells, it evidently depends on 

 the capacity of differently formed olfactory nerves for ap- 

 preciating them. It is astonishing how a dog will follow 

 at speed the scent of his master's foot, left, through a sock 

 and through a thick boot, on the gravel path on which it 

 has been only momentarily placed while walking, and de- 

 tect it also from other footsteps. A man might sniff away 

 for ever, and never recognize the presence of any odour 

 whatever on that path-way, except perhaps the smell of 

 earth. At the same time a man is struck offensively at 

 several yards distance by the stench of certain things 

 which the dog almost touches with his nose, and very 

 deliberately examines, before he seems to have made up 

 his mind. If this last example were not enough to show 

 that different olfactory nerves appreciate different odours 

 very differently, we all know the conclusive dictum of 

 the huntsman that his checked hounds had lost the 

 scent "all along o' them stinking violets." And so we 

 say the olfactory nerves of the otter are endowed with 

 the power of recognizing the scent left by a live fish in 

 the water. 



