OBSERVATIONS OF THE DWARF WEASEL
by
William E. Kearns, Assistant Naturalist

The morning of June 21 my son, Billy, came rushing into the house exclaiming that he had "nearly been run ever by a little mink...a tiny brown and tan one." The excited voices of the rest of the family who had gone out to see this bold creature, added the information that "he" was carrying a mouse.

Hastily securing my movie camera, I joined the folks and saw a very small weasel (later determined as Mustela cicognanii leptus) carrying a rodent of nearly twice the body diameter of the weasel. The weasel evidenced absolutely no fear of any of the five of us, but dropped his prey when he ran into my boot. While he scurried away for a distance of two or three yards to reconnoiter, I examined the animal which he had been carrying, and judging by its size, very short and nearly naked tail, digging claws, and mustaches, decided that it must be a brown pocket gopher (Thomemys fuscus fuscus).

The weasel quickly returned for his catch, and wanting to see what this miniature predator might do, I placed the gopher on the ground in a position at right angles and nearly five feet from where it had been dropped. Returning to my very boot tip, the weasel began an animated search for the gopher, and within a very short time had located it. Seizing the gopher, a huge burden for such a small creature, the weasel ran with apparently no effort for a distance of forty or forty-five feet to a neighbors porch. Here he was forced to drop his prey so that he might obtain a new hold to drag the gopher beneath the porch.

We followed him for half a block until he disappeared beneath a shed, not to reappear. So quick and rapier-like were his movements and so unpredictable, that I was unable to get any satisfactory movie shots.

Frank Andersen, District Ranger at Canyon, reports that during the week of June 12-18, he saw a very small weasel on two different occasions. The first time, the weasel was carrying a mouse (?) and ran across the road near the Canyon Ranger station. The second time, the same weasel, or one similar in smallness of size, ran across the road near the Haynes, Inc. Shop. On this occasion he was carrying a mole (?) of at least twice the body diameter and apparently half again the weight of the weasel. Mr. Anderson stated that the weasel was absolutely fearless of the group watching him, and that he approached to within a very few feet without evidencing the slightest alarm.

The weasel which we observed at Mammoth had a body length of about five and one-half inches, a tail of about half the length of the body, and behaved in a truly sophisticated and adult manner. Mr. Anderson agreed that the weasel, or weasels, which he observed at Canyon were about the same size and were probably Mustela cicognanii leptus.

Vernon Bailey in his book "Animal Life of Yellowstone National Park, page 147" says of the Dwarf Weasel (Mustela cicognanii leptus) "A very small weasel is reported as occasionally seen in the park, and a tiny track that I saw near Lewis Lake may well have been made by the dwarf weasel, which is found throughout the mountain region around the park. It is not so large as some of the mice that it hunts, but in general appearance and in habits it is a miniature of the other weasels, turning white in winter and brown in summer."