174 THE AUTHOR'S THEORY 



salmon have recovered their strength after spawn- 

 ing and increased in size, Nature takes away their 

 appetite, instinct prevails and they run up the rivers 

 to spawn. 



A NEW THEORY 



What, then, causes them to pursue and seize all the 

 moving objects they encounter prior to spawning ? 



It has been shown that the guiding loadstone of 

 their life is instinct, and instinct in this case makes 

 them destructive. A similar impulse pervades all 

 Nature, and teaches the parent to destroy or to 

 drive off any possible foes that are likely to endanger 

 the safety of its young. Salmon enter fresh water 

 for one purpose alone, and instinct teaches them that 

 all moving inhabitants of fresh water constitute a 

 future danger to the well-being of the defenceless 

 young which they must leave behind. Their instinct 

 therefore compels them to pursue, capture, and 

 destroy all the forms of life existing in the waters 

 which will be the future home of their young, and 

 which life may endanger the existence of their ova 

 or fry. Even in the smallest of the fish tribe, our 

 dear little bright sticklebacks, this instinctive desire 

 to attack and destroy all possible dangers to their 

 young is recalled in the delightfully simple rhymes of 

 Father Tuck's " Little Pets " series : 



" For if some fish or other thing 



To harm our nest draws near, 

 We bravely bite and fiercely fight, 

 To save our babies dear." 



