Fauna Series No. 5

Fauna of the National Parks — No. 5 The Wolves of Mount McKinley

CHAPTER FOUR:
CARIBOU

Description

THE CARIBOU is a circumpolar deer adapted to life in the Arctic. Both sexes carry antlers. The cow's antlers are small and branching, those of the bull large and picturesque with a well-developed brow tine extending over the nose from the base of one or both antlers. The blunt, curved hoofs provide a broad support for walking on the tundra or in snow. The long, thick coat of the bulls is dark brown, contrasting conspicuously with the pure white neck and mane and white stripe along the flank. The cows are similarly colored but the white is duller and the coat in general paler.

The shoulder height varies from 46 to 55 inches. The average dressed weight of 18 bulls, according to O. J. Murie (1935, p. 13), was 247 pounds, the heaviest 305 pounds. Of 6 adult bulls the average live weight was 366 pounds. The dressed weight of 12 adult cows averaged 148 pounds, and the average live weight of 5 adult cows was 213 pounds. A male calf taken by O. J. Murie in September weighed 75 pounds dressed, another 121 pounds live weight.

The caribou is a gregarious animal usually found in large herds. Sometimes the herds contain seven thousand or more animals, but a few hundred is the usual number. On the move much of the time, the caribou make extensive migrations which involve hundreds of miles of travel. The migrations follow general route patterns over a period of years, but have many variations and sometimes there are drastic changes. After passing over certain areas for a number of years, the animals may shift their ranges to entirely new areas. This migratory habit and the shifting of ranges are highly beneficial to the vegetation in that they tend to lighten use and give the forage plants opportunity for recovery. This is especially beneficial to the lichens (favorite caribou food) which recover slowly after being overgrazed.

According to O. J. Murie (1935), there are five principal caribou herds in Alaska, each of which is segregated sufficiently to be considered as a unit. There is, no doubt, some intermingling of animals from different herds. The animals in Mount McKinley National Park form a well-defined group, occupying a range which centers in the park and vicinity. They range over a region at least 300 or 400 miles in diameter; the exact limits are not known. At times this herd probably has some contact with the Yukon-Tanana herd which is the largest group. The total number of caribou in Alaska 20 years ago was estimated at more than a million. So far as known the status of the herds has not changed greatly since that time. However, there has been considerable hunting in recent years and the wolf population has been greater so that there may have been some decrease in late years. The park herd, numbering 20,000 to 30,000, constitutes only a small part of Alaska's caribou population.

Classification

The Alaska caribou have all been placed in the "Barren Ground group." Two subspecies have been recognized—Rangifer arcticus granti, to which the caribou on the Alaska Peninsula have been referred, and Rangifer arcticus stonei which includes all the other caribou in Alaska (O. J. Murie, 1935). There is great individual variation in antler form which has often given the impression that the woodland and Barren Ground caribou are both found in interior Alaska.

Numbers

During the 5 days between June 28 and July 2, 1941, about 14,685 adults and 6,900 calves were seen within the park, or a total of more than 21,000 caribou. There was not much possibility of duplication but no doubt some nocturnal migrants were missed. It is not known what part of the herd this count represents. The main bands of bulls, which had already moved west of Wonder Lake, were missed, and there no doubt were others which were scattered about to the west and elsewhere. It is safe to say that the Mount McKinley National Park herd numbers between 20,000 and 30,000.

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Last Modified: Thurs, Dec 20 2001 10:00:00 pm PDT
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