CONTENTS 



CHAPTER I.— Introduction 



Animal-life in the forest, the field, and the pond. Variations of 

 animals in different regions. Connection of animals in the 

 same region. Over-production in nature. The relation of 

 increase to the danger of destruction. The struggle for 

 life. Artificial selection. Natural selection. Transforma- 

 tion of species. Different animals of former days as the 

 parents of actual organisms. The theory of evolution. 

 Its predictions. Variation and heredity. Useful and 

 harmful animals. Modification of our animal -world 

 through civilisation - - - - 19 



CHAPTER II.— Mammals 



Life of mammals. Protective value of colour. Origin of 

 colour. Hibernation. Store-rooms. Increased produc- 

 tion or diminished peril of destruction. Why mammals do 

 not multiply more. The play of animals. Explanation 

 of play by rest and the accumulation of energy. Human 

 play. Imitation in play. Explanation of instinct. Instinct 

 and intelligence. Exercise of the mind in the games of 

 children. Pleasure in play. Conscious self-deception, 

 imagination. Play and art. The animal is at the threshold 

 of art. Sense of freedom in play. Games of children. 

 Attention. The use of curiosity. The mind of the 

 animal and of man 52 



CHAPTER III.— Birds 



Sexual selection. Choice of females. Rejection of the 

 hypothesis. Advance of the male's senses. Selection of 

 the strongest suitor. Explanation of coyness and the 

 animal coquette. Female selection inadmissible. The 

 love -dance. Selection of the apparent strongest. 

 Colours as means of distinguishing species. Use of 

 sounds. Pairing-calls. Origin and forms of song. In- 

 strumental music of the birds. Migration. Speed of 



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