VI 



SMELL— GENERAL 



Most naturalists and students of animal life have their 

 favourite groups of creatures, and this applies also to many 

 who study animals' senses. This aspect of the make-up of 

 living things — be they birds, insects, mammals or any other 

 kind, is absorbing taken as a whole; but some particular 

 sense may interest individual workers more than others. 



The power of scent, with which so many widely differing 

 animals are richly endowed, seems to me to be the supremely 

 interesting one. There is so much concerning scent about 

 which we still have a great deal to learn, and there is the 

 additional point that some animals have the ability to give 

 off as well as detect scents. 



In the mammals, scent is used for so many different 

 reasons. It may be used in trailing and capturing prey; it 

 can be the means by which an animal is warned of the 

 approach of enemies; scent is also used to recognize or 

 attract mates, and it is of great importance to some kinds 

 of mammals for marking and establishing territory. 



Smell is what is known as a chemical sense (as is taste) 

 and thus differs from sight and hearing. The use of the 

 word "chemical" means that particles of certain chemical 

 substances in solution are carried by the wind or diffused 

 in water, and these minute particles are detected in various 

 ways by the animals which have powers of scent. These 

 smells are naturally of many kinds : they may emanate from 

 a prowling foe ; they may come from plants or from animals 

 that serve as food ; they may be given off by an animal in 

 the breeding season in order to stimulate courtship and 

 subsequent mating. Whatever form they take they have to 

 be detected and received by olfactory organs which may 

 differ in structure and situation as widely as the smells them- 

 selves differ. 



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