PUTORIUS ERMINEA. 



63 



Adirondack region only, for I have not seen it elsewhere during- the 

 transition. It has been my experience, and the experience of the 

 man}' hunters and trappers that I have consulted on this point (an 

 experience resulting from the examination of upwards of an hundred 

 specimens caught at about the time of the first snow) that the Ermine 

 never assumes the white coat till after the ground is covered with 

 snow, which is generally late in October or early in November. It 

 frequently happens that the temperature of the atmosphere is many 

 degrees lower during the week or ten days preceding the first fall of 

 snow than at, or immediately subsequent to. the time of its deposi- 

 tion. Notwithstanding these facts, it is equally true that Ermine 

 caught up to the very day of the first appearance of snow bear 

 no evidence of the impending change. Within forty-eight hours, 

 however, after the occurrence of this snow-storm (provided enough 

 has fallen to remain and cover the ground; and regardless of the 

 temperature, which commonly rises several degrees soon after the 

 storm sets in) the coat of the Ermine has already commenced to 

 assume a pied and mottled appearance (often symmetrically marked 

 and strikingly handsome), and the change now commenced pro- 

 gresses to its termination with great rapidity. In early spring, the 

 period for the reversal of this process, the changing back from the 

 white coat of winter to the brown summer coat is determined by the 

 same cause — the presence or absence of snow. 



It may be asked " what induces the change in individuals kept in 

 confinement?" My reply is: certainly not tempcraturCy for it has 

 taken place when the animal was caged in a warm room, indoors. 

 The transition is more tardy in confinement than in a state of nature, 

 and may be coincident with the moult. In any case, we find the ex- 

 planation of its occurrence in the inevitable influence of hereditary 

 habit; and it is not rational to suppose that the temporary effect of 

 different conditions of environment would, in a single season, nullify 

 a tendency that is the outgrowth of causes that have been operating 

 for ages to bring about and perpetuate certain fashions for the pro- 



