22 
JOURNAL OF MAMMALOGY 
spruce-paper birch forests along the streams. The mating period at the head of 
the Kuskokwim is apparently in March. March 21, 1912,. tracks in the snow 
showed that a male had been pursuing a female the previous night. April 2 a 
female was taken containing four embryos, each about 5 inches in length; but 
another female taken April 16 contained no embryos. The skin of a male caught 
at the head of the North Fork of the Kuskokwim March 18, 1912, was perfectly 
prime; a female taken April 2 had several unprime spots on the skin; and the skin 
of a female taken April 16 in the same locality was very unprime. 
Gulo luscus (Linnaeus). Wolverine. — Several skins taken in the Yukon Flats 
were seen. Over most of interior Alaska the wolverine is rare or absent and we 
saw no signs of it. 
Mustela arctica arctica (Merriam). Arctic Weasel. — Specimens were taken 
at Tanana, at the head of the North Fork of the Kuskokwim, and by H. J. Christ- 
offers at Fairbanks. Tracks have been noted during the winter in nigger-heads, 
in the grasses and in sedges about lakes, in willows and alders along streams, 
in white spruce-paper birch forest, in black spruce forest, in burned forest, and in 
patches of blueberries and dwarf birches both in the valleys and on the hills at 
timber-line. One inhabited the walls of a cabin in the hills north of Tanana dur- 
ing October and November, 1911. Owing to their small value trappers seldom 
make any special effort to trap ermine, though quite a number are taken in 
marten traps. October 5, 1911, a male was obtained by H. J. Christoffers near 
Fairbanks on which the head and tail were mostly brown, the back about half 
white, and the belly pure white. Four days later a completely white male was 
obtained in the same region. At Tanana a fully white weasel was seen October 1. 
Weasels which were watched feeding on frozen pieces of rabbit and grouse did 
not handle nor hold the food in any way with the feet, but only with the mouth. 
When running the tail is carried off the ground usually at an angle of about 45 
degrees. Weasels when excited were several times heard to give a bark, some- 
what similar to the bark of the mink, though not so loud. 
Mustela vison ingens Osgood. Alaska Mink. — Common along the streams and 
lakes west to Bering Sea. Tracks were frequently noted on river-bars, in low- 
land willows and alders, in white spruce-paper birch forest, and in nigger-heads. 
Minks are most common in the grasses and sedges about lakes and swamps. 
Tracks of a few individuals were noted in black spruce forest on low hills, but 
these were apparently traveling overland from one river or lake to another. 
A specimen taken by H. J. Christoffers near Fairbanks August .1, 1911, was very 
fat and the skin was unprime. Two young taken near Tanana November 7 had 
skins not fully prime. The skin of a male taken March 9, 1912, near the head of 
the North Fork of the Kuskokwim was fully prime, but the skins of two males 
taken at the same place April 23 and May 2 respectively had unprime spots. 
The skin of a partial albino was seen in the possession of a trader at Tanana. 
A female taken May 13 near the head of the North Fork of the Kuskokwim con- 
tained a number of embryos, each about 16 mm. in length. A mink which en- 
tered a cabin north of Tanana to obtain some frozen pieces of grouse was watched 
for over an hour on the evening of November 1, 1911, at a distance of six feet. 
In feeding, it never used its front feet to handle or hold the food in any way, but 
manipulated it entirely by the mouth. When caught in a trap the mink often 
gives a hoarse bark. 
