298 
ZOOLOGZ 
(Putorius erminea) is a little larger than the least weasel, 
being 8-10 inches long; it is very fierce, and attacks larger 
animals; it can be utilized as a ferret. The ermine, like the 
northern hare, arctic fox, Hudson's Bay lemming, and other 
animals, turns white in winter. This is usually attributed to 
cold weather, hut Dr. Merriam thinks the change of color, 
which occurs suddenly, is due tosnow. If it were due to tem- 
perature why should not all animals which are active in win- 
ter change color; and if to snow, why should not the mink 
change color as well as the ermine ? Still it may in those 
animals which do change, have in the beginning turned 
white as the result of the glare of the snow on the eye 
and nervous system, the habit becoming inherited. Fishes 
and other animals change their color to white as the result 
of a change in the color of their surroundings. The 
change in such cases is due to the influence of light or 
darkness on the pigment or coloring matter of the skin or 
feathers or hair. A sudden fall of snow early in winter 
may cause an ermine to turn white within forty-eight 
hours, while for some unknown reason other animals, such 
as the mink, which are active through the winter, do not 
change; in early spring the change of color to the brown 
summer coat may also, as Dr. Merriam thinks, be due to 
the disappearance of the snow. It appears also that in 
Virginia and South Carolina, where there is either none or 
little snow, though the cold may at times be severe, that 
the ermine remains brown through the whole year. 
The mink {Putorius vison), larger than the weasel, being 
15-18 inches in length, is amphibious, swimming and diving 
after fish, while like the ermine it raids the poultry-yard. It 
emits a fetid and nauseating fluid from two glands situated 
at the base of the tail. It litters early in May in nests 
placed in burrows or hollow logs, and well lined with 
feathers, and sometimes, says Merriam, with the fur of 
the female. It does not turn white in winter. 
The dog tn>m\\y {CaJiidce) is represented by the fox, wolf, 
and dog. The gray fox [Urocyon Virginiamis), the com- 
