PACIFIC FISHER. Martes pennanti pacifica (Rhoads)

Field characters.—Size twice that of a large domestic cat; body rather slender (pl. 23a), tail bushy, more than half length of head and body; ears short and rounded. Head and body 20 to 25 inches (520-625 mm.), tail (without end hairs) 15 inches (375-380 mm.), ear 1-1/2 inches (35-40 mm.); weight (from specimens taken elsewhere in California) 8 to 10 pounds for males, 4 to 5-1/2 pounds for females. Coloration black on tip of nose, legs and feet, hind part of body and whole of tail; rest of body drab brown (many of the hairs black-ended), becoming grayish on head and shoulders; occasionally white spots on chest and belly.

Occurrence.—Moderately common resident in boreal region of Sierra Nevada. Winter specimens taken from Big Meadows and Tuolumne Grove Big Trees eastward to Chinquapin and floor of Yosemite Valley at Pohono Bridge. Seen in head of Lyell Cañon at about 11,000 feet altitude, July 18, 1915. Mostly inhabits forest. Solitary.

Information concerning the Pacific Fisher in the Sierras save for that obtained through trapping, is slow in accumulating. In fact, except for the specimens obtained from trappers in the western part of the Yosemite National Park during the winter months, we have only a single observation to record. The species seems to be even more retiring in its habits than is the Pine Marten.

The Pacific Fisher is a considerably larger animal than the Pine Marten, the weights of the two being in a ratio of about 3-1/2 to 1. Both exhibit the comparatively slender form of body which characterizes so many members of the Mustelidae, the chief family of the fur-bearers. The fisher is somewhat longer legged and its tail is decidedly longer proportionately than the marten's. In coloration the fisher is more varied than the majority of its relatives, and its fur is long as well as dense. Naturally, therefore, it is a species especially sought for the fur trade.

All of the winter records of the fisher in the Yosemite region are from a narrow belt of country in the western part of the Park because it is only or chiefly in that area that trappers have plied their trade. To judge from the habits of the fisher in other parts of its wide range, some individuals of the species probably remain during the winter months in the Canadian and even in the Hudsonian Zone of the Yosemite section. So far as we know no trapping or observation has been carried on in the heart of the high Sierras during the winter months; consequently, there is an almost total lack of information concerning the distribution and habits of the mammals which winter there. The one definite record for the fisher on the floor of the Yosemite Valley was made in the middle of winter, February 14, 1920, when an individual was obtained near the Pohono Bridge. The species does not stray onto the Valley floor very frequently, else, with the numerous campaigns of trapping (for coyotes) carried on there during the winters of different years, it would have been captured more often.

The fisher, to judge from its structure, especially from the sharp and curved claws, is an animal well fitted to climb trees. Its feet, at least during the winter months, are well furred between the toe and foot pads. This fact suggests that it also, travels about to a considerable extent on the snow. The habits of the fisher in the woods of Canada show it to be a truly carnivorous species, for it there destroys many of the fur animals caught in traps.

While four members of our party were ascending Mount Lyell on the morning of July 18, 1915, a good view was obtained of a Pacific Fisher. As we crossed a little depression at about 11,000 feet altitude, we scared the animal up and it bounded lightly away over the rocks and snow with the agility of a cat. The snow was 'pocketed' at this season and the animal had to leap deftly from one narrow ridge to another as it made off across the snow field. As it ran we noted the slender legs, slim body, and long tail, the light patch on the forehead and another on the back. The animal resembled a marten somewhat, but was larger. It made leaps of about 2 feet, and finally disappeared from sight behind the very last patch of stunted white-bark pines on the north side of Mount Lyell. When first seen, the fisher was about 200 yards off; as it ran it paused occasionally to look back in our direction. Its whole demeanor suggested that of a house cat making its way over a rough surface at a rather good rate of speed.