KEY TO THE LAND MAMMALS OF NORTH- 

 EASTERN NORTH AMERICA 



INTRODUCTION 



Originally outlined as part of my recently published Preliminary list of 

 the mammals of New York^, this " key " soon grew to the proportions of 

 an independent paper. As first planned it was intended to furnish a ready 

 means for finding — with the minimum of technical requirements — the 

 name of any wild mammal taken in New York. When the "key" was 

 separated from the " fist " its scope was extended to include the entire 

 mammalian fauna of the Atlantic slope of North America north of the 

 southern boundary of the upper austral zone. At the same time the 

 whales and porpoises were omitted. It is thus practically a key to the 

 land mammals of the Atlantic division of the fife zones represented in 

 New York state, since the upper austral zone is the southernmost of 

 these, and the arctic zone, florally at least, may almost be said to touch 

 the higher Adirondack peaks. Throughout I have endeavored to write 

 as non-technically as the subject will permit, that is to use no unex- 

 plained terms not to be found in a pocket dictionary. 



Life zones 



While the subject of life zones has been dealt with at considerable 

 length in the paper just referred to, a few words of definition are 

 necessary here. A life zone is simply an extended area over which the 

 fauna and flora are relatively homogeneous. As such areas are limited 

 chiefly by temperature, and their boundaries consequently determined by 

 isothermal lines, they normally assume the form of belts stretching from 

 east to west, or, to speak more exactly, arranged concentrically around 

 the poles. Therefore in passing from pole to equator a certain number 

 of these belts must be crossed. The forms of the life zones are distorted 

 by irregularities in the surface of the earth with their accompanying 

 variations in temperature. In the northern hemisphere mountain chains 



1 Bulletin of the New York state museum no. 29. Nov. 1899. 



