THE DOMINANT SENSES I9 



Marine life, other than fishes, includes an enormous 

 number of greatly varying creatures ranging from the minute 

 organisms which make up the animal part oi plankton to the 

 largest mammals of all, the whales ; and, of course, seals as 

 well. A complete book could be written about the senses of 

 all the numerous groups of animals that live in the sea ; but 

 reference will only be made to the most commonly studied 

 kinds in dealing with the separate senses in following 

 chapters. 



Birds, like ourselves, for the most part live in a "seeing 

 world", and the complex way in which the eyes of different 

 Families work is one of the most interesting aspects of bird 

 life. Sight plays a major part in feeding, courtship, and 

 escape from enemies, but in considering this sense it must not 

 be forgotten that, as is the case in other groups of animals, 

 the sense of hearing plays a big part too. 



It seems quite certain that many kinds of birds have a 

 well-developed sense of taste, yet it is thought that with the 

 exception of geese and ducks, they are very deficient in 

 respect of smell. This is curious considering that the two 

 senses of smell and taste are so closely linked. To me it seems 

 so curious that I am tempted to suggest that much further 

 research is needed before accepting the frequently expressed 

 opinion that very few birds can smell at all. 



The sense of touch is not one that at first would seem to be 

 important to birds; but their beaks (bills) and even their 

 bodies are capable of very delicate tactile perception. The 

 nestlings of many species are, in the first few days of their 

 lives, very dependent upon vibrations to stimulate a feeding 

 reaction ; and there are other examples of this kind of thing 

 which will be given in greater detail later. 



When we reach the Mammals we are dealing with animals 

 most of which live in a world of smells ; but hearing once 

 more plays a large part in mammalian life and to a greater 

 extent than is often thought. We may see a mammal in a 

 zoo, apparently asleep, and under conditions of complete 

 safety; yet deep sleep as we know it is most likely a rare 

 phenomenon, for even when no enemy can threaten, the 

 ears are constantly on the alert. This, of course, shows how 

 deep-seated is the necessity for self-preservation. It is most 



