Fauna Series No. 5

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

CHAPTER TWO:
WOLF (continued)

Hunting Range

The East Fork wolves were known to move readily over a range at least 50 miles across. During the denning period their movements radiated from the den, and ordinarily the wolves traveled a dozen or more miles from it. But greater distances were readily traveled. In the spring of 1941, when a band of five or six thousand caribou calved some 20 miles away, the wolves traveled this distance nightly to prey on the calves.

In the winter of 1940-41 there were many caribou along the north boundary of the park, which attracted the East Fork wolves. The hub of their movements was shifted in that direction, but they continued at intervals to make trips back through the part of the range which they used most in summer. These trips were probably made in search of mountain sheep for there were no caribou along the route. Wolves seem to enjoy traveling, and these excursions may in part have been made because of their habit of being on the move. Wolves are often reported to have a circular route which they take a few times during the month, but the East Fork wolves on a number of occasions traveled both ways on the same route.

The family at Savage River lived the year round in that locality. They ranged westward 10 miles to Sanctuary River, which was normally the east boundary of the range of the East Fork wolves. I do not know how far to the east these Savage River wolves wandered, but possibly 12 miles to the Nenana River or farther. The east-west breadth of their range appeared to be less than that of the East Fork wolves, but the former may have wandered farther in a north-and-south direction. The center of the Savage River range was some 35 miles east of the East Fork den.

The Toklat River den was about 22 miles northwest of the East Fork den. Nothing was learned of the range of this family but it probably overlapped the range used by the East Fork wolves. Wolves lived the year round at Wonder Lake, about 40 miles west of East Fork.

The different wolf families seemed to have rather definite year-round home ranges which overlapped somewhat. It was significant that within the large range of the East Fork wolves almost every wolf seen was recognized as belonging to that band.

The winter distribution of the wolves in Mount McKinley National Park seems to be only locally influenced by the movements of the caribou. When the caribou winter along the north boundary the wolves spend most of their time among them, but in years when the caribou are absent the wolves desert this part of their range. Instead of moving off with the caribou they shift their attention to mountain sheep.

It is generally believed that the wolves follow the caribou herds but to what degree this is true is not well known. Since the caribou appear to be the main food supply of the wolves in interior Alaska it is to be expected that the wolves gravitate toward the caribou range and, in the presence of this food supply, flourish. When caribou make large permanent shifts in their ranges the wolf distribution probably becomes adjusted to the shift, but perhaps not all at once. The wolves probably do not as a rule follow particular herds and it seems likely that in general their movements on the caribou range are similar to those observed in Mount McKinley National Park. Local circumstances no doubt influence movements in each region. Where hares, moose, or mountain sheep are available, there would be less need for the wolves to move with the caribou.

Intraspecific Intolerance

The only data bearing on intraspecific intolerance are a few incidents, which are only suggestive. Of course the rather definite home ranges that the wolf families appear to have, also suggest that an intolerance to strange wolves exists. A strange wolf, probably belonging to the Savage River family, was reported to have traveled up high on a mountain on one occasion in order to avoid five East Fork wolves at Teklanika River. Such behavior could occur, however, where there was considerable tolerance.

An incident at the East Fork den indicates the treatment that a strange wolf may receive. On May 31, 1940, all five adults were at home. Between 10 a. m. and noon the mantled male had been on the alert, raising his head to look around at intervals of 2 or 3 minutes. Several times he changed his position until he was about 200 yards above the den. Such prolonged watchfulness was unusual, but it was explained by later events. Shortly after noon the four wolves at the den joined the mantled male and they all bunched up, wagging tails and expressing much friendliness. Then I noticed a sixth wolf, a small gray animal, about 50 yards from the others. No doubt the presence of this wolf had kept the mantled male so alert during the preceding 2 hours.

All the wolves trotted to the stranger and practically surrounded it, and for a few moments I thought that they would be friendly toward it for there was just the suggestion of tail wagging by some of them. But something tipped the scales the other way for the wolves began to bite at the stranger. It rolled over on its back, begging quarter. The attack continued, however, so it scrambled to its feet and with difficulty emerged from the snapping wolves. Twice it was knocked over as it ran down the slope with the five wolves in hot pursuit. They chased after it about 200 yards to the river bar, and the mantled male crossed the bar after it. The two ran out of my sight under the ridge from which I was watching.

Four of the wolves returned to the den, but the mantled male stopped half way up the slope and lay down facing the bar. Presently he walked slowly forward as though stalking a marmot. Then he commenced to gallop down the slope again toward the stranger which had returned part way up the slope. Back on the bar the stranger slowed up, waiting in a fawning attitude for the mantled male. The latter snapped at the stranger which rolled over on its back, again begging quarter. But the stranger received no quarter, so again it had to run away. The male returned up the hill, tail held stiffly out behind, slightly raised. When he neared the den the four wolves ran out to meet him, and there was again much tail wagging and evidence of friendly feeling.

The unfortunate stranger's hip and base of tail were soaked with blood. It was completely discouraged in its attempt to join the group, for it was not seen again. It may have been forced to leave the territory of this wolf family, for if it were encountered it probably would have been attacked again. Judging from the usual reaction of a group of dogs to a strange dog, such treatment of a strange wolf would seem normal. Small groups of wolves may be treated like this lone wolf, hence it is advantageous for minor packs to find territories where they are unmolested. Such rough treatment of individual wolves, if it is normal, would tend to limit the number of wolves on a given range.

The Wolf Pack

Wolves normally travel in packs. The smaller packs consist of a single family group, the larger ones perhaps of two or more families. E. W. Nelson (1887, p. 237) reported wolf packs in 1880 numbering as high as 50, but usually containing from 6 to 10 individuals. A trapper reported seeing tracks of a pack of 24 wolves north of Mount McKinley National Park in the winter of 1939—40. At Wonder Lake a few years ago a pack of 22 wolves was seen and another of 19 was reported by a Ranger.

In 1940 the East Fork pack consisted of 7 adults and 5 pups. In August 1941, it was made up of 5 adults, all part of the previous year's pack, and 10 pups, offspring of two pairs. In 1940 the Savage River pack consisted of 3 adults and 6 pups in August, and in December this same group was traveling together. When there are 2 or more females in a group, the adults, plus the pups, might make a sizeable band. Three females could easily have 15 or 20 pups, and these, together with 6 or more adults, might make a pack of 20 or 25 wolves. When there is more than 1 female in a band it is probable that they den quite near each other as did the 2 females at East Fork in 1941.

Although the East Fork wolves often traveled together, at other times they traveled singly or in various combinations. Quite often a member went off alone for a time but rejoined the band daily, so far as I could tell. There is at times the "lone wolf" which lives by itself, at least for a period. In the winter of 1940—41 a lone wolf spent several weeks around Park Headquarters. It apparently picked up scraps at the garbage heap. During the day it often rested in the woods less than half a mile from headquarters.

Because wolves rely mainly on large animals, the pack is an advantageous manner in which to hunt. A lone wolf would ordinarily have difficulty in catching sheep, but several wolves working together can hunt sheep rather successfully. Adult caribou are sometimes brought down by a single wolf, but it is no doubt easier for two or more to hunt them.

The size of the pack may be limited by the law of diminishing returns. Beyond a certain size, advantages may disappear. A pack might be so large that, after the strongest members had finished feeding on a kill, there would be little or nothing left for the rest. In such a situation hungry ones would go off to hunt again, and the strong ones, already fed, would remain where they were. There thus might result a natural division of a band which was too large to function advantageously for all its members. One would expect that where game is scarce the wolves would operate in smaller units than where food is abundant.

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