While occupied in this rivalry for food they became surprisingly pugnacious. If one was working at the rice pile and another rat or a pocket mouse approached, it immediately darted at the intruder and drove it away. The mode of attack was to rush at an intruder and, leaping upon its back, give a vigorous downward kick with its strong hind feet. Once I saw a pocket mouse kicked in this way. It was knocked over and for a minute or more afterwards ran about in an erratic course, squeaking loudly as though in much pain.
Sometimes the pursuit of one kangaroo rat by another continued for twenty yards or more. By the time the pursuer returned another would be at the rice pile and it would immediately dash at the victor of the former fray and drive him away. In this way there was a constant succession of amusing skirmishes.
Sometimes an intruder, bolder than the others, would run only two or three yards and then suddenly turn and face the pursuer, sitting up on its hind feet like a little kangaroo. The pursuer at once assumed the same nearly upright position, with its fore feet close to its breast. Both would then begin to hop about watching for an opening. Suddenly one would leap at the other, striking with its hind feet exactly like a game cock. When the kick landed fairly on the opponent there was a distinct little thump and the victim rolled over on the ground. After receiving two or three kicks the weaker of the combatants would run away.
The thump made by the kick when they were fighting solved the mystery which had covered this sound heard repeatedly during my nights at this camp. The morning light revealed a multitude of little paired tracks made by the combatants in these battles. Such tracks in the sand have been referred to as the “fairy dances” of these beautiful little animals, but the truth revealed proves them to be really “war dances.”
THE BANDED LEMMING (Dicrostonyx nelsoni and its relatives)
(For illustration, [see page 519])
Banded lemmings are unique among the mouse tribe in their change from the rufous brown, or gray summer coat to pure white in winter. With the assumption of the white winter fur a thick, horny, padlike growth develops on the underside of the two middle claws of the front feet, which is molted in spring when the winter coat is lost. For an animal living in the far North the usefulness of a white coat in winter is evident, but no good reason is apparent for these curious claw-pads.
The summer coat varies remarkably in color and color pattern, and many of the lemmings in their beautiful shades of chestnut, browns, or grays are very handsome. They are more heavily proportioned than field mice and the very long fluffy fur, which completely conceals the rudimentary ears and tail, tends to exaggerate their size.
The banded lemmings form a strongly marked group, containing a number of species inhabiting circumpolar regions. In North America they occur nearly everywhere in the arctic and subarctic parts, including Greenland, most of northern Canada, including the Arctic islands, and a large part of Alaska, including some of the Aleutian Islands.
They range as far northward as vegetation affords them a proper food supply and have been well known to many of the explorers of those stern northern wilds. To the southward they extend into the subarctic northern forests, where they usually keep to the open barren areas.