120 Instinct. 



of the severity of the winter or the height of the 

 coming freshets. He certainly makes serious blun- 

 ders. He sometimes builds his house where the 

 water leaves it in winter and the frost renders it 

 useless. And, again, he builds it where the freshets 

 overflow it and compel him to shift for himself 

 among the ice and water. The Muskrat provides 

 for winter as many other animals do, but the un- 

 certainty of the season is a condition which seems 

 to be an important element that he has to contend 

 with in his struggle for existence. The thickness 

 of the walls of his house, according to which the 

 severity of winters is predicted, seems to depend 

 upon the condition of the weather while the house 

 is building, rather than upon any foresight of its 

 builder as to the coming winter. As the Muskrat 

 cannot control the height of the water, as does his 

 cousin the Beaver, he is often compelled to add to 

 his house as the water rises and then again as it re- 

 treats, while he makes his canals and approaches 

 deeper. He is often kept at work upon his house 

 till winter closes in. What affects one lodge is like- 

 ly to affect all more or less, in the same region ; 

 and thus in meeting the exigencies of the case, from 

 day to day, these animals have had credit for a fore- 

 sight which they do not possess. 



The safety of all species is that their Instinct 

 provides for the average season, — our protection 

 against many animals, that is, against their too abun- 

 dant increase, is that their Instinct fails to make 

 provision against the extremes of seasons. When 

 certain insects become abundant, it often happens 



