WEASELS 89 



a Mountain Weasel happened along and nearly consumed the squirrel 

 before it in turn was caught in another of the traps in the same set. On 

 the same day the greater portion of another weasel caught elsewhere had 

 been eaten, but there was nothing to indicate the identity of the animal 

 which had attacked the victim of the trap. It is evident from the first 

 mentioned case and from other trapping experiences not specifically cited 

 that weasels will eat dead flesh, even when not fresh. 



A Mountain Weasel three-fourths grown, living in a den under a willow 

 clump at the edge of the lake, was taken at Mono Lake Post Office on 

 June 30, 1916. There were many droppings at the entrance to the den. 



Sierra Least Weasel. Mustela muricus Bangs 



Field characters. — Size small and form slender; our smallest carnivore (fig. 9a); 

 body about as large as that of Tahoe Chipmunk; tail small, round, about % length of 

 head and body. Head and body 6i/^ inches (159-161 mm.), tail 2% inches (59 mm.), 

 ear % inch (8 mm.), weight about 2 ounces (56-62 grams.). Coloration in summer 

 season chocolate brown above, under surface white; end of tail blackish. 



Occurrence. — Sparse resident in Hudsonian Zone along Sierra Nevada. Eecorded at 

 Ten Lakes (9200 feet altitude), October 10, 1915, and at Vogelsang Lake (10,350 feet), 

 August 31, 1915. Lives in or about rock slides. Solitary. 



The Sierra Least Weasel, as its name suggests, is much smaller than its 

 better known relative, the Mountain Weasel. We obtained two specimens, 

 as recorded above, and no others were seen ; it would seem from our experi- 

 ence both in the Yosemite region and elsewhere that the species is decidedly 

 less numerous than is the Mountain Weasel. The Least Weasel is a member 

 of a rather wide ranging group which fills some small corner in the economy 

 of nature not occupied by the larger species. So far as our local informa- 

 tion indicates, the Least Weasel is an associate of the Pine Marten, Yosemite 

 Cony, and Bushy-tailed Wood Kat. 



At Vogelsang Lake on August 31, 1915, the senior author, while making 

 the rounds of his traps before sunrise, heard two conies across the lake basin 

 (pi. 18a) 'screeping' vociferously. Upon going to the rock slide, he saw 

 these animals running excitedly in and out of the crevices between the 

 rocks. Presently a Least Weasel appeared, crossing between two rocks. 

 Soon, it put its head out from under a flat rock within 30 feet of the 

 observer, who shot it. The inference that this weasel is a regular enemy 

 of the conies and is so recognized by them seems justified. 



Pacific Mink. Mustela vison energumenos (Bangs) 



Field characters. — Body size about that of California Ground Squirrel, but tail short, 

 about half head and body (fig. 9c); head and body ll^-lB^d inches (297-337 mm.); 

 til 6-6% inches (150-170 mm.); ear about 1/2 inch (11-14 mm.); weight 13l^-18% 

 ounces (377-530 grams). Coloration deep, dark brown, only a little paler on under 

 surface; end of tail blackish. 



