PEEFACE 



THE authors present this book as an elementary ac- 

 count of animal ecology that is, of the relations of ani- 

 mals to their surroundings and of the responsive adapt- 

 ing or fitting of the life of animals to these surroundings. 

 The book treats of animals from the point of view of the 

 observer and student of animal life who wishes to know 

 why animals are in structure and habits as they are. 

 The beginning student should know that the whole life 

 of animals, that all the variety of animal form and habit, 

 is an expression of the fitness of animals 'to the varied 

 circumstances and conditions of their living, and that 

 this adapting and fitting of their life to the conditions 

 of living come about inevitably and naturally, and that 

 it can be readily studied and largely understood. The 

 ways and course of this fitting are the greatest facts of 

 life excepting the fact of life itself. In this kind of 

 study of animals every observation of a fact in animal 

 structure or behavior leads to a search for the signifi- 

 cance, or meaning in the life of the animal, of this fact. 

 The veriest beginner can be, and ought to be, an independ- 

 ent observer and thinker. It is the phase of the study of 

 zoology which appeals most strongly to the beginning 

 student, the phase which treats of the why and how of 

 animal form and habit. At the same time this phase is 

 that to which the attention of the most advanced mod- 

 ern scholars of biology is rightly and chiefly turned. The 



