BEAVER 



Joseph Mailliard, in a note in the Journal of Mammalogy, 

 February, 1925, writes: 



"This Httle village (Eagleville) lies at the eastern base of 

 the Warner Mountains, on the edge of a long strip of meadow 

 land that is irrigated from the mountain streams. East of 

 this narrow meadow is Middle Lake, which, except for a small 

 laguna at its southern extremity, is a lake only in winter and 

 spring. The rest of the year it is but a bare expanse of alkali 

 sand. East again of the lake is a desert of sand, lava and 

 sagebrush that stretches across the close-by state line far into 

 Nevada. 



"In this desert, at a point about two miles east of Eagle- 

 ville, it was my good fortune to encounter colonies of both the 

 Columbian kangaroo rat, Dipodomys ordii columhianus 

 (Merriam), and the Oregon kangaroo mouse, Microdipodops 

 megacephalus oregonus A-Ierriam. These colonies, which 

 appeared to be small ones, were found scattered among the 

 low, brush-grown sand dunes and hummocks that cover that 

 part of the desert. In walking over the dunes my foot 

 frequently broke through the surface into the burrows, many 

 of which appeared to be unoccupied. 



"The main reason for supposing that the colonies were 

 limited in the number of their respective members was that it 

 seldom was found profitable to trap in a colony for more than 

 one night before moving the traps to another sand dune. 

 Some mornings, however, even when the trap lines had been 

 laid out on absolutely fresh ground, there were rodent tracks 

 all around and often close up to many of the traps, without a 

 single one of them having been sprung or a particle of the 

 bait — consisting generally of rolled oats — having been touched, 

 but in such cases no change was made in the location of the 

 trap line and usually a comparatively fair catch was made the 

 following night." 



Family Castoridae. Beavers 



Resembling the Sciuridee but cheek-teeth not rooted, crown 

 pattern with re-entrant enamel folds instead of tubercles; 

 mandible heavy; size large; form thickset; tail broad, flat, 

 and scaly; habit aquatic. 



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