66 MOSTLY MAMMALS 



the ermine (or stoat) are white at all seasons, but this does 

 not seem to be authenticated. 



Observations are wanting as to whether the changes of 

 coat and colour in the mountain hare bear any relation 

 to the appearance and disappearance of snow, or whether 

 they occur regularly at the same season of the year. In 

 the case of the ermine in the Adirondack region of New 

 York, Dr. C. H. Merriam tells us that in this animal the 

 white livery is assumed only after the first fall of snow, 

 while the resumption of the brown coat does not take 

 place till the snow begins to melt. Unfortunately, he 

 says nothing in regard to change of coat. The late 

 Dr. Coues stated, however, that in the case of the ermine 

 the bi-annual change of coat takes place at the same 

 season, but that it depends upon the condition of the 

 temperature at the time whether the new coat differs in 

 colour from its predecessor. In other words, the change 

 from brown to white might be due either to shedding the 

 coat or to bleaching of the hair subsequent to such 

 shedding. The case of the mountain hare is, however, 

 strongly suggestive that the colour-change is in all instances 

 coincident with the shedding of the coat. 



It is, of course, quite evident that the assumption of a 

 white winter livery by mountain hares and ermines living 

 in regions where the snow lies on the ground for a con- 

 siderable portion of the year is for the purpose of rendering 

 such animals as inconspicuous as possible when in their 

 native haunts. And, so far as we know, such a change 

 is universal among the species named when dwelling in 

 high northern latitudes. 



There is, however, another animal inhabiting the North 

 Polar regions of both hemispheres in which the change 

 to a pure white winter dress is limited to certain indi- 



