The bulls begin to spar soon after rubbing off the velvet. Even before serious fighting occurs, a bull may show his superiority to some of his companions. At this time two strange bulls do not hesitate to approach each other and, with no preliminaries, join antlers and try to drive each other back. These early fights are brief and on a more or less friendly basis. A sharp prong may cause a bull to pull away and be unwilling to resume sparring. But later, when a bull has acquired cows, up to a dozen or two, he herds them constantly, and fights all challengers.
The single reddish calf is generally born in May. His strength and speed develop rapidly so that he is soon able to follow the herds in their hurried travels. By autumn he has acquired a coat similar to that of the adults.
A close relationship exists between the caribou and the wolf, one that has prevailed for thousands of years. Although the wolf largely subsists on caribou over much of the north, natural adjustments have prevailed so that caribou have prospered in the presence of wolf populations. Wolves prey extensively on caribou calves in spring. When a wolf takes after a herd of caribou containing calves, both old and young hold their own for a time. But soon a calf may begin to fall behind the racing herd, its endurance not quite up to that of the others. It is overtaken and eliminated. Natural selection has operated, a culling operation that over eons of time would seem to have evolutionary significance.
Grizzly bears capture a few very young calves. Encouraged by their early-season success they continue chasing calves long after the calves have gained strength and speed enough to readily escape. After a few failures, I suspect that a grizzly learns that the calf-catching season has passed and is no longer tempted to gallop ponderously and fruitlessly with excess power but not sufficient fleetness to capture fleeing calves.
Moose
Alces alces gigas
The northern conifer forest, stretching across the continent, is the home of the moose. In Alaska he has reached his greatest size. A mature bull weighs 12 to 15 hundred pounds, and his huge, palmate antlers have reached a record spread of about 80 inches.
At a distance the moose appears to be black except for his long, light-colored stockings. The large head is supported on a short neck, a shoulder hump is prominent, the nose is loose and bulbous. A special feature is the bell that hangs from the throat. The legs are inordinately long and the hoofs sharp.
Moose may be discovered anywhere along the park road. They are frequently to be seen between Savage and Sanctuary rivers, and along Igloo Creek. In the Igloo Creek area three or four old bulls may generally be found spending the summer together, their daily movements usually covering about a half-mile or less. We speak of the moose as a forest animal, but it is often found the year round in willow brush beyond timber. It is not uncommon to see moose in the willows on the treeless passes such as Sable and Polychrome.
The principal food of the moose is browse. In summer the leaves are stripped from the branches; at other seasons the twigs are eaten. Willows and dwarf birch are the chief browse species in the park. Aspens and cottonwoods are relished but are not plentiful enough to be very important. Alder is generally eaten only sparingly in winter. Farther south over the moose’s range, firs and hemlock are highly palatable in winter. The long legs enable the moose to reach high in his browsing. It is not unusual to find winter browsing sign 12 feet or more from the ground where the moose have stood on snow to feed. Tall willow brush and aspen saplings are often broken over in order to get at the twigs out of reach. The muzzle may be used for this, or the limb may be grasped in the mouth and pulled down. Many broken willows are evident on the bars along Igloo Creek.
The long legs and short neck make grazing difficult. In Wyoming I once saw a cow and calf feeding on mushrooms, a delicacy. Reaching the ground was not easy—the calf dropped to his knees, and the cow was for part of the time down on one knee.