PREFACE 



The senses of animals — and of man — are what keep them, 

 and us, in touch with the environment; they enable the 

 naturalist to observe the animals he is studying and the 

 animals to observe him and, very often, to avoid being 

 observed by him. We have long been interested in this 

 fascinating aspect of natural history and we hope that our 

 book will be acceptable to all who are interested in animals, 

 and in particular that it may be useful to the younger people 

 who are entering upon this delightful subject in their school 

 biology classes. Perhaps, too, those with more experience will 

 find some matters set forth that will suggest new lines of 

 profitable study. 



In writing the book it seemed to us best to divide it into 

 two parts : the first explaining what the naturalist can observe 

 in the field ; and the second giving the more technical back- 

 ground of the way in which the senses of animals function. 

 In both parts we have tried to avoid the heavy going of too 

 many technical terms, and wherever it has been necessary 

 to use the language of science we have, we hope, sufficiently 

 explained it. 



All branches of natural history are absorbing, but we think 

 that attention directed to the link between ourselves and the 

 subjects of our study will be rewarding to all naturalists 

 whether they be ornithologists, entomologists, mammalogists, 

 or specialists in any of the other numerous subdivisions of 

 knowledge about the living world. We trust they will find it 

 as full of interest and problems as we have. 



L. Harrison Matthews 

 Maxwell Knight 



