)74 



THE NATIONAL GEOGRAPHIC MAGAZINE 



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the; common brown rat 



The large series shows the ordinary forag- 

 ing gait; the smaller one, to the right, shows 

 the travel at low speed. In all, the tail mark 

 is a strong feature (see pages 525 and 531). 



the group is represented by the well-known 

 species Mtistela vulgaris. In North America 

 several species are known which, between them, 

 share all the continent from the Arctic coast 

 south to Nebraska and Pennsylvania. On the 

 desolate islands extending from the mainland 

 far toward the Pole their place seems to be 

 taken by the ermine. 



The dwarf weasels appear to be less numer- 

 ous and, as a consequence, less known in most 

 parts of America than in England and north- 

 ern Europe. Our most northern species, 

 iJiistela rixosa, sometimes called the "mouse 

 weasel," occupies Alaska and northern Canada 

 and has the distinction of being the smallest 

 known species of carnivore in the world. In 

 this connection it is interesting to note that 

 in Alaska we have associated on the same 

 ground the least weasel and the great brown 

 bear, the smallest and the largest living car- 

 nivores. 



Least weasels are characterized by the same 

 swift alertness and boldness so marked in the 

 larger species. In fact they are, if possible, 

 even quicker in their movements. Once when 

 camping in spring among scattered snowbanks 

 on the coast of Bering vSea, I had an excellent 

 opportunity to witness their almost incredible 

 quickness. Early in the morning one suddenly 

 appeared on the margin of a snowbank within 

 a few feet, and after craning its neck one way 

 and the other, as though to get a better view 

 of me, it vanished, and then appeared so 

 abruptly on a snowbank three or four yards 

 away that it was almost impossible to follow 

 it with the eye. It was beginning to take on 

 its summer coat of brown and was extremely 

 difficult to locate amid the scattered patches 

 of snow and bare moss of the tundra. Cer- 

 tainly no other mammal can have such flash- 

 like powers of movement. 



They feed mainly on mice, lemmings, shrews, 

 small birds, their eggs and young, and insects. 

 Mice furnish a large proportion of their prey 

 and weasels have often been seen following the 

 runways of field mice. Their small size enables 

 them to pursue mice into their underground 

 workings as readily as a ferret enters a rabbit 

 burrow. They also climb trees and bushes with 

 great agility, although nearly always seeking 

 their victims on the ground. The mice upon 

 which they prey are often so much larger than 

 the weasels that they cannot be dragged into 

 the dens. The weasels continue in full activity 

 throughout the winter and constantly burrow 

 into the snow in search of their prey. In the 

 snow or in the ground the holes of this animal 

 are about the diameter of one's finger. 



In the Old World the small weasels are re- 

 ported to have several litters in a season, each 

 containing five or six young. At Point P)arrow, 

 Alaska, a female captured on June 12 still con- 

 tained twelve embryos. This indicates that 

 only one litter a year would be born tliere, and 

 that Mustela rixosa is more prolific than its 

 European representative. 



In the more soutliern latitude least weasels 

 live in forests and about farms, sheltering 

 themselves under logs, brush piles, stone walls, 

 and similar cover. They are always restless 

 and filled with curiosity regarding anything of 



