EDITOR'S INTRODUCTION xiii 



Finally, there remain subjects which are of such recent 

 growth that their principles have never yet been treated in a 

 comprehensive way. Such, for instance, are developmental 

 and comparative physiology, animal behaviour, and ecology. 

 From the point of view of the rapid growth and expansion of 

 general biology, it is these subjects which it is at the present 

 moment most important to summarise in brief text-books, 

 since otherwise the multifarious knowledge which we have 

 already attained regarding them remains locked up in scattered 

 papers, the property of the specialist alone. 



The present volume deals with a much misunderstood and 

 often underrated subject. If we leave out Hesse's Tiergeo- 

 graphie auf okologischen Gnmdlage, which deals with faunas 

 and major habitats and animal adaptations rather than with 

 ecology sensu stricto, hardly any books dealing with the subject 

 have been published since Shelford's fine pioneering work 

 of 1913, Animal Communities of Temperate America. 



The subject is also so new and so complex that it is only 

 of recent years that principles have begun to emerge with any 

 clearness. It has further suffered from taking over too whole- 

 heartedly the concepts of plant ecology and applying them 

 directly to animals instead of seeing whether the difference 

 between animal and plant biology did not of necessity intro- 

 duce a difference in the principles governing animal and plant 

 ecology. 



Mr. Elton, ever since I had the good fortune to have him 

 as my pupil at Oxford, has been largely occupied with the 

 problems of animal ecology and the quest for guiding principles 

 in the subject. He has been fortunate in having field ex- 

 perience in the Arctic, where the ecological web of life is 

 reduced to its simplest, and complexity of detail does not hide 

 the broad outlines. He has also been fortunate in early be- 

 coming preoccupied with the subject of animal numbers ; or, 

 I should rather say, he early showed characteristic acumen in 

 seeing the fundamental importance of this problem. He is 

 finally fortunate in having an original mind, one which refuses 

 to go on looking at a subject in the traditional way just because 

 it has always been looked at in that way. The result, it 



