Mammals of Mount McKinley National Park
Part 3
At McKinley we have an opportunity to preserve a northern flora and fauna. But the future of the wolf is precarious because the home range of the park wolves extends beyond park boundaries into territory where the wolf has no protection, where there is a bounty on his head. The silencing of the longdrawn call of the wolf would be a tragic loss to the human spirit.
Coyote _Canis latrans incolatus_
So far as known, the coyote has always been rare out in the park. Along the Nenana River, however, I frequently have heard his song. Here he seems to find conditions more favorable for his way of life. Perhaps it is the presence of the snowshoe rabbit in this low brushy country that attracts him.
The coyote weights about 25 pounds on the average. His color is brownish with black-tipped hairs intermingled. Color variation in coyotes is so slight it is not noticeable in the field; he does not have the black, whitish and various color patterns that are present in the wolf. The muzzle is long and pointed, ears well developed, eyes sharp.
As a field biologist I have had an opportunity to observe coyotes in many regions. In Yellowstone I made a 2-year study of its relationships with other animals because it had been feared by some that he would destroy the antelope, bighorn, and deer, if not controlled. The study showed that the coyote there lived chiefly on meadow mice and pocket gophers in summer, and carrion in winter, and that he had no harmful effect on the large ungulates.
On the San Carlos Indian Reservation in Arizona the coyote was blamed for cattle losses. Here a study showed that the basic cause of losses was over-use of the range and that where grazing was good all losses were insignificant. Cattlemen are finding this true and are beginning to appreciate the usefulness of the coyote as a curbing influence on rodent depredations. In addition to a meat diet, which includes great quantities of grasshoppers in season, the coyote feeds extensively on fruit. On Isle Royale, in Lake Superior, I found it feeding on sarsaparilla berries; in Jackson Hole, Wyoming, on silverberry and quantities of haw; in Arizona, on manzanita and juniper berries, the latter being the winter staff of life.
The coyote is best known for his song, which in all its variations, symbolizes the spirit of wildness and remote country. J. Frank Dobie in his _The Voice of the Coyote_ expresses the sentiment of many when he writes: “I confess to a sympathy for the coyote that has grown until it lives in the deepest part of my nature.”
Red Fox _Vulpes fulva alascensis_
The fabled red fox is abundant, widely distributed over the park and frequently seen. Silver, cross, and red color phases, along with some intermediate variants, are well represented, and two or three of these types frequently show up in a single litter. The prominent white tip on the tail distinguishes the fox from the coyote and wolf.
Hundreds of dens are scattered over the countryside, many more than are used in any one season. They are located indiscriminately in spruce woods and out on the open tundra miles from the nearest tree. Each pair has a selection of old dens to choose from, but often they occupy favorite sites year after year. During a season, a family sometimes moves from their first choice to a den nearby. The connecting burrows of a den usually have 5 or 6 entrances and one I examined had 19.
The young are born the early part of May. By June the blackish, blue-eyed, chubby pups may be seen walking about clumsily. At this age they are nursed in the open. One mother that I often watched almost always nursed her five pups from a standing position. Only twice did I see her lying on her side to nurse. As the pups grow they become slimmer and the eyes turn brown and the coat color changes so that the different color types can be identified. Although nursing seems to cease toward the end of June, the cubs remain at the den into September.
While the male travels far to hunt, the vixen remains at home to watch over the pups. Most of the time she is curled up at the den or perhaps a hundred yards away on a prominence. When she wishes to nurse the pups or give them food, she puts her head in the mouth of a burrow and calls softly “mmmmm,” “mmmmm.” If they do not come forth, she may go to another entrance and call. But usually they respond at once. A sharp, guttural “klung” has the opposite meaning; when the pups hear this warning they scurry into a burrow. This command is often given after the pups have nursed and the mother wants to go off a short distance to lie down.
The female exhibits extreme friendliness toward her mate. When he returns to the den after an absence she greets him with tail-wagging, face-licking and much wriggling of her body. He is less demonstrative and acts tired, which he probably is after several hours of hunting. She picks up his offerings—usually mice or ground squirrels—eats her fill or, if not hungry, carries the booty to the burrows and calls to the young. He moves off to one side to rest. She sometimes watches for his return from various points. One evening a vixen impatiently moved from one lookout to another for over 2 hours before the male arrived and received her warm welcome.
Mice and lemmings are the staple all-year food, but in summer the ground squirrel may make up about half the diet. When snowshoe hares and ptarmigan are plentiful, they become prominent in the diet. Carrion is especially attractive in winter, and the fox attends carcasses and curls up on the snow to wait until the wolves and wolverine have eaten. He robs wolf and wolverine caches, and he sometimes has his own caches robbed.
In the latter part of July the foxes go berrying, for they are fond of fruit. Blueberries and crowberries are everywhere available for the picking. The berries are also eaten in winter sometimes, it is said, quite extensively when mice are scarce.
Foxes appear to be well able to take care of themselves. They can outrun the grizzly, wolf, and wolverine. When the golden eagle swoops at him he stands on watch with his bushy tail erect and straight as a ramrod. The eagle dares not strike.
Lynx _Lynx canadensis_
The lynx manner is one of independence, confidence and complacency. He walks through the woods with dignity, looking neither right nor left. Of course, he is not as oblivious as he appears to be. He may even stop to watch you, but only briefly, and then he continues sedately on his way.
His long legs are thicker than seem necessary to support the lean body, but they are no doubt valuable for long jumps and pouncing. The large, widespreading feet serve him well as snowshoes, and strong, curved claws enable him to scramble readily up a tree. The eyes are startlingly big and yellow and the throat ruff gives to the face a squarish look. Long, glistening black tassels adorn the ears. The stub tail, about 4 inches long and tipped with black, serves to register emotions. The winter fur is soft and grayish, with few markings except for the facial pattern; the summer coat is more tawny.
Nature has bestowed on the lynx a snowshoe fixation so that he spends his nights and days thinking and dreaming of rabbit dinners. So dependent has he become on the rabbit for his main course that his numbers flourish and wane in the wake of rabbit statistics.
During the period between 1954 and 1956, when lynx were abundant in the park, I made a study of their food habits by analyzing several hundred lynx scats. In addition to rabbits, the lynx had fed considerably on ptarmigan and in summer on ground squirrels. This part of the diet increased as the rabbits decreased. But with the decline of the rabbits, the supplemental foods did not suffice to maintain the population, and the lynx became scarce.
In the winter of 1907-08, Charles Sheldon noted two instances of lynx preying on sheep. The rabbit population had crashed and the lynx had turned to other sources for survival. One lynx that made its attack on a sheep from ambush found the prey rather large, for in the ensuing struggle he received some severe bruises. He apparently was driven to hunting animals out of his class. About 2 years after rabbits disappeared in the Kuskokwim River region a number of years ago, lynx did some preying on reindeer in winter by leaping on their backs and biting the neck. The lynx were said to have attacked the reindeer only that one winter. During periods of food scarcity, lynx have also been observed to prey on each other.
The young are born in May in a cave, or perhaps more often, under a windfall. The gestation period is about 60 days.
In early June, 1955, I saw a lynx in the spruce woods near Savage River. As I stood watching I heard crying sounds up in the woods. The lynx disappeared in the direction of the crying. I followed and saw the parent under a windfall as it was departing with a baby in its mouth, the last of a litter it was moving. Snow and rain had fallen and the mother was carrying her family, one by one, from under an inadequate windfall to another about 250 yards away. The new home was under a brushy spruce that provided a dry shelter in any kind of weather. So well hidden and secure did the mother feel that she barely opened her sleepy eyes even when approached within 20 feet.
How empty the woods and willow patches become with the decline of the rabbits and the departure of the lynx. It is like an empty stage after the actors have finished their play and departed. Scattered through the quiet woods are their signs of life and activity, but the action has stopped. On the tall willows, 6 feet from the ground, is the gnawed white rabbit-line, where rabbits had sat on the snow and gnawed the bark within reach. In places the ground is littered with severed twigs, many of them partially gnawed. And everywhere one encounters tufts of rabbit fur and hind legs, left on the green moss, signifying rabbit tragedies and lynx banquets. But the rabbits will return again to dance in the moonlight, and the lynx will be back in his rich domain walking with stately and regal step.
Wolverine _Gulo hylaeus_
The fabulous wolverine is a powerful and picturesque member of the weasel tribe weighing up to 35 pounds or more. Because of his stocky build and long hair, he resembles a small bear. Frequently the large hoary marmot is mistaken for him—there is considerable similarity. But the broad yellowish-tan stripe on the sides of the body is distinctive. A whitish collar, not always visible, extends across the throat. The tail is short and bushy; the sharp, well-developed claws are whitish. His range is circumpolar and extends southward in the mountains to Colorado and California, but he is now scarce south of Canada.
The wolverine in late years seems to have become more plentiful in the park; nevertheless, it is always considered something special to see one. They range from river bottom to ridge top, are found in the woods or in open country miles beyond timber. Perhaps because of the open view, he is frequently seen on the low passes, especially on Sable Pass.
In winter the track of the far-wandering wolverine is frequently seen. In his usual gait he bounces along with back arched. Each jump usually leaves a set of three imprints; the one in front is made by a hind foot; the middle imprint is made by a hind foot falling in the track of a front foot; the rear imprint is made by the other front foot. As in the tracks of a hopping rabbit, the hind feet tend to be brought up ahead of the front feet.
The wolverine readily climbs trees. One winter, near a moose carcass, tracks in the snow showed that a wolf had chased a wolverine up a tree on two or three occasions. If the two had met in the open the threatening posture of the wolverine would, no doubt, be sufficient to discourage attack. When attacked by a dog, a wolverine has been seen to lie on its back in a defensive attitude, a position that was effective. Powerful ripping claws and jaws face the attack.
Not much quantitative information has been gathered on his food habits. I have watched him pouncing on mice and suspect that mice (voles) and lemmings are the most important items in his diet. In summer he captures ground squirrels, sometimes by doing some digging. Once I noted that he had dug out a wasp nest hidden in the ground. The calves of caribou and moose, when very young, are no doubt potential victims. But observations indicate that even a caribou can ward off an attack on the young calves. Such items would, of course, be unimportant in the wolverine’s total economy. His wide wanderings in winter would seem to be helpful in finding carrion. In rich wild country, considerable carrion probably comes his way. I have found the wolverine attending a frozen moose carcass for a number of days. When a carcass is not frozen, he carries away what he can to cache for later use.
The gestation period is said to be about 9 months. The breeding apparently takes place in summer. The fertilized eggs, after brief development, lie unattached and dormant in the uterus for several months. Some time in midwinter the eggs become attached to the wall of the uterus and the more usual development takes place. (The marten and short-tailed weasel have a similar breeding history.) Females have been found in a nursing condition in early April. Along Igloo Creek, Mr. and Mrs. Edwin C. Park watched a mother nurse two young at least two-thirds grown.
According to Peter Krott, in his fascinating book about the wolverine in Europe, this fierce animal makes a friendly pet. The author, in the beginning, made a business of acquiring young wolverines for sale to zoos. Because the animal was rare and intriguing, the demand was great and the prices remunerative. But Mr. Krott and his wife became fond of the wolverines and found it ever harder to dispose of them. Soon they ceased selling them, and, instead, kept them as pets and allowed them to roam freely over wild country. Studies were made of their habits. Their wolverines might wander far and stay away for several days, but they would return at intervals.
The wolverine is at home in the McKinley wilderness. Here we have the rare opportunity of seeing him in his natural environment.
Marten _Martes americana actuosa_
The marten is long and lithe, and its graceful activity is conspicuous. The usual color is a rich brown, shading to blackish on the feet and tail. The face is grayish with a short, dark line extending upward from the inner corner of each eye. A large orange throat and breast patch is very striking in most individuals. The fur is soft and long, the tail is long and well-furred, and serves to register various emotions. The marten is alert to sounds and this is indicated by its well-developed, broad ears.
The body is 16 to 17 inches long, and the tail, including hair at tips, 8 or 9 inches. A large male may weigh up to 2½ pounds. The female is somewhat smaller than the male.
The marten is found in the forested parts of the park along the northern and eastern boundary. In winter, I have noted a few tracks in the big spruce woods south of Wonder Lake. In Wyoming, I have found martens in rock slides beyond timber, the rock crevasses furnishing the desired protection.
At one time the marten was thought to depend on the red squirrel for his daily fare, but recent studies indicate that ordinarily relatively few red squirrels are eaten. A food-habits study made at Castle Rocks near the northwest corner of the park showed that the martens there were living primarily on meadow voles and the red-backed mouse. Blueberries were eaten in winter as well as in summer. In Wyoming, I have found martens feeding extensively on blueberry, rhamnus, haw, and mountain ashberries by choice at a time when voles and other foods were plentiful. Like the fox and coyote, they have a strong predilection for berries. In slide rock, they manage to capture an occasional pika.
The marten breeds in July and August, but the young are not born until 9 months later. The long gestation period for such a small animal is due to the delayed attachment of the fertilized egg to the uterus. Except for the period when the female is followed by young, and during the breeding period, martens travel alone.
In Grand Teton Park, Wyoming, where I had much opportunity to observe martens, I found that, although they seldom captured a red squirrel, in their vagabond life over their home area, they did use red squirrel homes for sleeping. The marten might spend a few days resting in a squirrel’s spare nest, then move on to another squirrel domicile for a few days. The squirrels suffered only the inconvenience of an unwanted guest, and perhaps the temporary loss of a favorite bed.
Mink _Mustela vison ingens_
The mink is the amphibious member of the weasel family. He lives along rivers and lakes and probably forages more in the water than on land. Fish, frogs, insects, snails, crayfish, rabbits, muskrats, and mice all appear on his bill of fare. In the country between the mouth of the Yukon and the Kuskokwim River, the mink is said to subsist largely on Alaska blackfish (_Dallia pectoralis_). So abundant were the mink in the area that the Eskimo were called “mink people.” The muddy waters in this watery region apparently supported enough blackfish for both the mink and the natives. This fish is said to have been the chief food of the natives. It is very tenacious of life. Kegs of live fish, packed densely, were kept for food in the dwellings. A steady slow rotary movement of the mass of fish brought each fish to the surface at intervals for a gulp of air. When a frozen blackfish is thawed, it is said to become as lively as ever.
Mink tracks have been noted along the Nenana River, but over most of the eastern half of the park the mink is rare.
River Otter _Lutra canadensis yukonensis_
The otter is rare in the park. It was reported present in Wonder Lake some years ago and tracks in the snow were reported at Savage River. It probably occurs in the Nenana River, along the eastern park boundary.
The otter, a member of the weasel family, has become adapted to life in the water. His body is about 3 feet long, and his long muscular tail is over a foot long. His cousin, the sea otter, plentiful in the Aleutian Islands, is much larger and more specialized for an aquatic life.
I have watched a family of otters in Grand Teton Park fishing for an hour or longer. They kept diving steadily, and occasionally one would come up with a small fish which he would proceed to eat, beginning at the head. Larger fish are taken ashore. Trout, chubs, and suckers were available but numerous droppings showed that the otter were feeding chiefly on the chubs and suckers. The fish taken were no doubt those most easily captured. A few crayfish were also eaten. This particular family was living in a large beaver house also occupied by beavers. They entered their chamber by land and apparently lived upstairs above the beaver’s part of the house with its underwater entrance.
In winter the otter frequently travels over the snow from one piece of water to another. In these travels he slides on his belly down all slopes and sometimes even on the level. In play, a family may repeatedly climb a mudbank or a snowbank to course down a slide leading into water.
Short-Tailed Weasel _Mustela erminea arctica_
Two species of weasel occur in the park. The larger one with a black-tipped tail is called the short-tailed weasel, and the smaller one with an extremely short and all-white tail is the least weasel.
Both weasels are brown in summer and white in winter, a protective coloration no doubt useful in escaping detection. In some southern parts of their ranges these weasels remain brown all year, and in intermediate areas part of the population turns white in winter and part of it remains brown. It is apparent that climate has an effect on coat color, the specific factor being the presence or absence of snow on the ground.
It has been pointed out that the short-tailed weasel is much larger in the north than in the southern part of the range. In Wyoming and Colorado, where the tiny least weasel is absent, the short-tailed weasel approaches the least weasel in size and probably fills that weasel’s niche in the environment.
The food of the short-tailed weasel probably consists chiefly of various species of meadow mice and lemmings. Observations indicate that ground squirrels and rabbits may occasionally be captured. Shrews no doubt are also on the menu.
In winter, weasel tracks form an odd pattern. Their jumps are alternately long and short, and often they make an erratic trail. Frequently the tracks show that the weasel disappears and travels beneath the surface for a stretch before reappearing.
Even though weasels are not very palatable because of their well-developed musk glands, they nevertheless are often preyed upon. It is a case of coyote or fox capturing any small animal that moves and examining the victim afterwards. Weasels are often left uneaten.
Least Weasel _Mustela rixosa eskimo_
The range of the least weasel is circumpolar. In North America it is found over most of Alaska and Canada, and southward to Montana, Kansas, North Carolina. It is widely dispersed but apparently nowhere abundant. This tiny weasel is only 6 to 6½ inches long with a maximum tail length of 1½ inches. It is the smallest living member of the carnivores and weighs no more than a meadow mouse. The tail is pure white, lacking the black tip present in other weasels.
I have a record of four specimens from the park. One captured in a mousetrap was 5½ inches long, the tail measuring less than 1 inch. I found a dead one at an eagle perch on a ridge top, and remains of two others on gravel bars, apparently discarded after being captured.
A sourdough on the Koyokuk River with whom my brother and I stayed one night, had a least weasel spending the winter with him. It had the run of the cabin and was very tame.
Apparently the chief food of the least weasel is mice, some of them about as large as himself.
Snowshoe Rabbit _Lepus americanus macfarlani_
Like the ptarmigan and the northern weasel, the snowshoe rabbit, or varying hare, each autumn changes from a dominantly brown summer coat to a white winter ensemble. (In Washington where snow is scarce in its habitat, the snowshoe rabbit remains brown the year round.) His coat color blends at all seasons with his background, so all he need do to be fairly sure of escaping visual detection is to have confidence in his camouflage and sit motionless. The fur is so long, thick, and warm that he can sit all day in fifty below zero weather without freezing. His large hind legs are equipped with snowshoe feet, an obvious advantage in snow country.
The most favorable rabbit habitat is the brushy country along the east and north boundaries. Here a few may always be found. Out in the park they are quite scarce except in those years when the population is at or near a peak.