Hibernation is correlated with the period of food scarcity. When autumn snows arrive, the bears continue for a time to dig roots, to excavate ground squirrels, and, in places, to feed on berries. But as autumn progresses, the ground freezes, berries become buried by snow, and general feeding conditions deteriorate. The daily regime of gorging over several months results in warmly furred bears prepared to wait out the winter months in underground chambers. The denning period, judging from general observations, extends from late October and early November to April (Fig. 29).
On 11 October 1939 a lone bear was observed digging a den on a high, rather steep slope. A foot of snow lay on the ground at the time. The following spring, on 29 April, I had my first view of the den. Three fresh trails led out from the den over the snow, indicating that the bear had been visiting or occupying it recently. The thin sod roof over the chamber caved in during the summer. The chamber was about 4 feet from the entrance and about 5 feet in diameter.
Years ago (29 March 1922) my brother Olaus, traveling by dogteam, stopped at the Knight Roadhouse down the Toklat River several miles north of the park. The story of a bear encounter related to him at the roadhouse included the information that a bear was digging a den in November. The story is of interest and I shall quote from Olaus' diary:
Sometime later I obtained measurements of this bear's skull from Richard H. Manville. These measurements indicated that the bear was a large male.
Apparently a den may be dug long before the time of retirement. On 22 July 1953 I came upon a freshly dug den on Cathedral Mountain. The entrance was about 27 inches high and 24 inches wide. The tunnel was about 12 feet long and slanted upward slightly. At that time no chamber existed. On 23 August a chamber 4 feet by 3 feet had been hollowed out at the far end, the longer dimension at right angles to the tunnel. The den was intact 6 years later. I noted that cinquefoil bushes near the den had been nipped off in past years and brought into the chamber. Remnants of dry grass and herbaceous material also were present. One-quarter mile from this den another den had been freshly dug that penetrated about 5 feet.
Another den on Igloo Mountain was dug on a gentle slope in a patch of willows. The burrow was 9 feet long. About two bushels of dry vegetation had been pawed out of the burrow and lay on the large dirt mound. The nest material consisted chiefly of blueberry, cinquefoil, and willows. Twigs were mixed with a lot of moss, and bear hairs were mixed in with nest debris.
The burrow of one old den had caved in but the roof over the chamber was intact. The chamber measured about 3-1/2 feet by 5 feet and the burrow leading to it was about 9 feet long. Lambs were scampering about the den, and sheep had rubbed against the exposed sod.
In November 1920, O. J. Murie visited two unoccupied dens in the Savage River area similar to those I have described. One of these dens was dug in gravelly soil at the edge of timber near the base of a spruce where it had been necessary to bite off a number of roots. Because bears can so easily dig a den in loamy soil, it is probable that they dig new dens rather than search for one used previously. The 12 dens that I know about have been dug by bears. If a natural cave were available, I expect it would be used at times. O.J. Murie found a cave on the Alaska Peninsula occupied by a brown bear, and I was told that a natural cave at the head of one of the rivers in McKinley Park had been occupied. Black bears in more southern climes, such as Pennsylvania, may hibernate in a hollow, but I suspect that in northern country the bears seek the shelter of a burrow or a cave.
The dens I have visited were located throughout the bears' range so it appears that bears do not necessarily move into lower country to hibernate (Fig. 30).
The grizzly is a carnivore that cannot capture enough prey for subsistence. He hunts methodically mice and ground squirrels, but the small size of these rodents makes this hunting too time-consuming to satisfy his hunger or nourish his huge bulk. He is too slow to capture caribou, moose, or mountain sheep except for offspring a day or two old. On the coast of Alaska spawning salmon in some streams are an important food during some periods, but this food item is not available in the park. Carrion flesh is appreciated but occurs only sporadically.
To subsist, the grizzly has turned to vegetation for a staple, dependable diet. He has learned to exploit a variety of these foods.
I have summarized my 19-year observations of bear feeding in Table 7. This table demonstrates seasonal changes of foods and their relative contribution to the grizzly's diet. June is divided into two parts because a major change in food habits usually occurs in that month. Most of these observations are from several years in the 1960s when I made a special effort to document food habits. In earlier years I did not always note what food was being eaten when I observed bears. Each observation is of a lone bear or a family unit. Details of food use are in the annotated list of grizzly foods and some of the sections on relationships with other animals.
Table 7. Tabulation of foods eaten by grizzlies in Mt. McKinley National Park from observations of feeding, 1945-1970.
Annotated List of Grizzly Foods in McKinley National Park
Roots: The principal food of the grizzly in the spring is the thick, fleshy root of the peavine (Hedysarum alpinum americanum). These roots become an important food again in autumn. The root resembles that of dandelions, and the flavor suggests garden peas.
Roots other than peavine also have been reported to be part of the grizzly's diet. In some diggings I have noted the exposed roots of rock fireweed (Epilobium latifolium) and possibly some had been eaten. The underground stems of coltsfoot (Petasites frigidus) appeared to have been eaten a few times. I have seen 7 or 8 feet of shallow sod composed of mountain avens (Dryas octopetala) rolled up like a carpet. But this may have been exploratory rather than to feed on the roots. One autumn I watched a grizzly digging roots near the top of a ridge on a steep, barren slope. From a distance I could detect only scattered cinquefoil (herbaceous) and a little rock fireweed. The bear moved about searching for plants with his nose, and digging a foot or more before reaching the root he sought. I thought that perhaps he was feeding on a root I had not recorded because peavine roots usually are near the surface and do not require much digging. The following day I examined the diggings and learned that the bear had been hunting peavine root. Because of the gravelly nature of the soil, the stems were long and the roots buried deeply. In practically all diggings that I examined the peavine was present and obviously was the species of root sought.
Root digging is the chief occupation of grizzlies during May and early June. In 1947 my latest record in spring for this activity was 10 June. In 1962, when there was an unusually heavy winter snowfall, and in 1963 when spring was very late, root digging continued undiminished until the middle of June, and the latest root digging noted in each of these 2 years was 21 June. The duration of the spring root-feeding period thus depends on the weather and the location (elevation, etc.) and it varies with the individual bear.
In late summer and early autumn some root digging is resumed, but berries usually continue to dominate the diet of most bears at this time. On 29 July 1953 I watched a grizzly dig a few roots; in 1961 a bear was digging roots on the East Fork bar on 7 August, and a few fresh diggings were seen on the Toklat bar on the same day. In 1960 two 2-year-old bears were observed digging roots almost daily from 8 to 25 September. In September there is considerable root digging, even when berries are available. At the time the two young bears mentioned above were occupied with digging roots, many other bears were feeding chiefly on berries. In 1963, a year in which the berry crop failed, more fall root digging than I had ever observed occurred.
On many old river bars and ridge slopes the peavine is abundant and distributed uniformly. Diggings often are so extensive and concentrated that they resemble plowed fields. One or both paws, usually both, are used to turn over chunks of sod and expose roots. When the paws are placed on the sod, the bear loosens a chunk with a series of pulling jerks, using his whole body in the effort. The roots exposed in the turned-over sod are then eaten, and more are uncovered by raking the soil from them with slow, delicate strokes. When small cubs are present, they may forage in the mother's diggings and uncover roots that she missed. When a bear starts chewing on a root, 6 or 7 inches of it may protrude from the mouth. A few times I have seen a bear use a paw to scrape dirt off a root held in the mouth. In places where sod has not yet formed and peavine plants are scattered, bears may move about more as they search for the plants with their nose. Like much of the vegetable food the bear eats, many roots seem to have undergone relatively little digestion when they appear in the scats (Figs. 31, 32).
Extensive areas over some of the old river bars have been rooted annually for years. In the digging, enough sprouts may develop to insure a continuous source of plants for the future. But in some favorite, more limited areas large roots apparently become depleted sufficiently to cause their neglect for a year or longer, until the young plants develop roots large enough to be attractive.
On the upper East Fork River, an old bar is covered chiefly with mountain avens. For 15 years or more it showed scarcely any digging by bears, but recently this extensive bar has been dug heavily, in both spring and fall. The plant succession was not monitored, but judging by the appearance of the present vegetation, the peavine has invaded the dense sod of mountain avens. In parts of the bar, adjacent to the diggings and stretching far beyond, peavine appears to be invading but the plants are still too young to have developed large roots.
Overflow ice, sometimes 10 feet or more in thickness, may form on some river bars during the winter and protect the peavine from the bears during the spring. If peavine is not available in spring, it would be during the autumn rooting period. These overflow ice deposits may vary in depth, extent, and specific location from year to year. Thus, a tendency for a natural rotation of rooting areas exists but may seldom develop enough to have a significant effect (Fig. 33).
When bears excavate roots on a slope the possibility of areas enlarging and developing progressive erosion is real. Generally, however, although the location of diggings can be noted in later years, a healing process sets in and the bare spots recover gradually. The disturbed but uneaten roots of peavine and other species in the diggings may sprout and form a good growth the same year the diggings occurred. The open slope above the east end of the Toklat bridge was excavated heavily by bears for 2 or 3 years in the early 1960s. In 1963 when I examined the slope after this rather heavy use, I found that the diggings had healed so rapidly that at a short distance they were not obvious. In 1964 and 1965 I saw no bears digging on these slopes.
The recovery on river bars also may be rapid. In 1962 I photographed fresh diggings on the East Fork River bar that were so contiguous that the area had the appearance of a plowed field. When visited the following year, with some expectation of taking additional pictures, most diggings were hidden by a new growth, especially of peavine which had sprouted from pieces of roots left in the turned-over sod.
A small area along the Toklat River that was excavated thoroughly by bears in 1939-41, was, by 1963, grown over by dwarf birch, and a patch of cottonwoods 10 or 15 feet tall had grown up in one area that had been used heavily.
The braided channels of the rivers in the park are always shifting, invading and eroding old river bars covered with vegetation, and else where permitting, over the years, the development of new vegetated bars. Thus these areas, used by bears as a source of roots, are not static. In a national park our policies protect these natural processes so that no effort is made to freeze the environment at some particular stage.
In other parts of Alaska roots also are an important part of the grizzly's diet. O. J. Murie examined 151 scats gathered in the upper Sheenjek River area. The scats were not dated accurately, many of them being old when found, but they showed that bears fed extensively on peavine roots. Fifty-five of the 151 scats collected contained peavine roots. O. J. Murie (1959) stated that spring food for the brown bear on the Alaska Peninsula consisted chiefly of grass and roots. On Montague Island, Sheldon (1912) reported brown bears feeding on the roots of skunk cabbage (Lysichiton).
In the scat table for McKinley National Park (Table 8), note that 105 of the 810 bear scats examined contained roots. Of these 105 scats, 82 contained only roots. These figures and my observations indicate that when bears feed on roots they concentrate on them almost exclusively.
Table 8. Occurrence of food items in 810 grizzly bear seats collected in Mt. McKinley National Park, 1947-1970. Numbers in parentheses are occurrences of 50 percent or more of the item in seats. The number of scats examined in each period is shown at the top of each column.
Grasses and Sedges: The spring root diet is abandoned as the new green vegetation becomes available. This may be in late May or, in the higher elevations (3,000 to 4,000 feet), during the first 2 weeks of June. In 2 years when the season was late, green grass was not eaten until 15 June, and in one year, not until 18 June. In those years, feeding on roots continued longer than usual. There may be a considerable overlap between the spring root-feeding and grass-eating periods. Bears may still be feeding extensively on roots when they first begin to find patches of green grass. During this transition period, some bears may be feeding only on roots when others have discovered that green grass is available and are concentrating on it.
The first grass available is a tall species (Calamagrostis canadensis). It is not a favorite but because it appears early, it is sought eagerly. To get at the green shoots the old mass of dry stems and blades sometimes is pushed aside with muzzle or paw. At this time of grass scarcity a bear may make a full bite to get only a single grass shoota ludicrously big effort to get so little. When vegetation growth begins it is rapid and favorite green foods become so available that early spring grazing on this particular grass soon ceases.
The favorite grass is Arctagrostis latifolium. This species resembles Calamagrostis but bears have no difficulty differentiating between them.
The juicy-stemmed Arctagrostis grows in moist hollows and draws and along streamlets. It is associated closely with palatable herbaceous species, so that in his grazing the bear may feed for a time on grass and then shift to some of the herbs. Arctagrostis is perhaps the most important of the green foods in the areas I observed in the park.
When berries become available later in July and early August, the feeding on grass and other green foods slackens and the bears turn to these fruits. In areas where the berry crop is good the grass feeding may be abandoned rather abruptly.
In years when the berry crop is generally poor, grass continues to be eaten throughout August and in early September. In 1963, when the season was late and the park suffered an almost complete berry failure, bears continued to feed extensively on green vegetation during August and well into September. On 27 August 1963 two families on Sable Pass fed throughout the day on grass, sedges, and herbs. Very little sedge is eaten as a rule, but at this time, because the snowfields in the hollows were slow in melting, sedges were still young and tender whereas most other green foods were old and tough. On 11 September 1963 a family and a lone bear fed extensively on green foods including a sedge (Carex podocarpa). On 16 September a fresh scat in the Thorofare area contained only blades of mature sedge that were still green but no longer tender in a wet, flat area nearby. In 1964 the berry crop was also poor and as a result green foods were eaten extensively during the usual berry-feeding season.
Bears swallow grass and sedge with relatively little mastication and much of it appears in the scats, little altered after its passage through the digestive tract.
Grizzlies have been found feeding on grass and sedge in other areas. On the Sheenjek River (Brooks Range) O. J. Murie recorded grass and sedge in 46 of 151 scats. He found the brown bear feeding on grass on the Alaska Peninsula in early June. Sheldon (1912) reported brown bears on Montague Island feeding on a special kind of grass above timber. In Yellowstone National Park I have seen grizzlies grazing on grass as early as 11 May. In Glacier Bay National Monument I saw a black bear grazing steadily in a large patch of sedges, and it is probable that grizzlies there would seek the same sedges.
Of the 810 scats examined, grass was found in 263 of them. Seventy-nine of the scats contained only grass.
Horsetail: Horsetail (Equisetum arvense) is relished by both grizzlies and black bears. Feeding on horsetail begins in late May, as soon as the new green growth becomes available, and continues through the summer. As late as 28 August I have found fresh droppings containing only horsetail. On 6 September 1964 I saw a mother and yearling feed on a fresh growth of horsetail. (At this time most of the plants were old, and some patches had turned brown.)
In looking through some of O. J. Murie's notes I found a few references which showed that black bears in Alaska are also fond of horsetail. Horsetail also is relished by Dall Sheep and is eaten by ground squirrels and Willow Ptarmigan.
I have watched grizzlies feed steadily in a patch of horsetail, then switch to sourdock, Boykinia, and Arctagrostis (grass) for a change. Horsetail is one of the grizzlies' favorite summer foods. It is possible that some of the other species of Equisetum are also eaten occasionally but I have no such records, and one or two species growing in ponds and eaten by moose probably are palatable to bears.
That bears concentrate frequently on horsetail is indicated by the fact that of the 97 scats that contained this plant, horsetail made up 100% of 53 of them.
Saxifrage (Boykinia richardsonii): The showy Boykinia, with its large rounded leaves and conspicuous cluster of white blossoms growing in a spike, occurs in damp hollows, along streamlets, and in openings among tall willows. It is often associated with other food species eaten by grizzlies. Flower heads, leaves, and parts of stems are consumed. A bear may at times take a liking to the flowers and move along cropping off one flower cluster after another and neglecting the leaves. Once, however, I watched a bear bite off stems 6 to 8 inches below flower heads, eat the stem and leaves attached and discard the flower. Usually, a bear feeds briefly on this plant, then turns to grass, horsetail, or other species if they are associated, shifting back and forth between species. Once I watched a bear in an extensive patch of this big-leaved plant, concentrating on it for 2 hours. In 1963, when berries were scarce, I saw much late summer feeding on Boykinia. On 27 August some of the plants whose growth had been delayed because of late melting snowbanks were sought eagerly. The stunted, bunchy plants were grazed almost completely, the bears biting off one leaf at a time, doing a thorough job rather than picking haphazardly here and there as they usually did. In that same year the entire contents of a fresh scat examined on 22 September contained only Boykinia, an unusually late record. This species, along with some of the other herbaceous food plants that generally are not listed specifically in scat tables, is underrepresented in the scat analyses. Many of the droppings containing grass also had herbaceous remains.
Sourdock (Rumex arcticus): Sourdock grows luxuriantly in moist hollows and along small streams and is eaten extensively by bears. On 7 July 1960 two 2-year-old cubs fed on this species for 30 minutes, although other favorite foods such as horsetail, Boykinia, and grass were present. After a siesta, the two cubs fed for a long period on grass (Arctagrostis), then for a time on sourdock again, and later on horsetail. Only the leaves and stalks of the sourdock are eaten. The seed stem is bitten off 6 or 7 inches below the large seed head and maneuvered into the mouth so that the seed head is cut off and discarded. On 22 July 1961 I watched two spring cubs feeding on sourdock. They bit off the stem near the ground, ate stem and leaves, and discarded the seed heads as deftly as did older bears. While I watched, the mother of the cubs did not feed on this sourdock but sought other species of vegetation.
Mountain Sorrel (Oxyria digyna): One of the first sources of green food in early summer is mountain sorrel, with its round leaves and sour taste. In 1963 a mother and two 2-year-old cubs were observed grazing on the mats of this plant that grew in a draw among tall willow brush. The growth was so short that the bears practically had to gnaw it off the ground, yet they fed extensively on it. This species is eaten frequently, but is a less important item than some other herbaceous food plants because of its limited availability.
Viscid Oxytrope (Oxytropis viscida): This species of peavine grows extensively on old river bars, especially near the headwaters. In late June and much of July some bears spend hours grazing on the flowers and leaves. One year in June, at the head of East Fork River, I saw seven bears (a mother and two spring cubs, and two sets of twins about 3 or 4 years old) feeding on this species. In 1965, from 7 to 12 July, two families fed extensively on this species on the west branch of East Fork River. By August most grazing on this plant had terminated. Another year in August, I found several old scats at the head of East Fork River that contained this species, but in fresh scats only a trace was noted in one of them. Although some bears feed a great deal on this species, others apparently seldom visit areas where it is plentiful and consequently use little of it. Viscid oxytrope only was present in 131 of the 140 scats in which the species occurred.
Willow (Salix spp.): I have noticed grizzlies eating willow on only a few occasions. On 4 May 1940 a yearling cub was observed eating a few catkins, and on 4 June 1955 another yearling cub was seen feeding briefly on them. On 23 May 1961 I watched a bear biting casually at willow twigs as he walked steadily on his way. On 23 June 1962 a mother and yearling ate a few willow leaves.
Bergman (1936) found that willow catkins are an important early spring food of the Asian grizzly in Kamchatka. He writes: "Before the hills become green, willow catkins are eaten with the greatest relish. Hunters agree that these catkins play a great role in the springtime food of the bear; one frequently sees willow bushes, stripped of their catkins, surrounded by bear tracks."
It is possible that the McKinley bears feed more on catkins than my observations indicate. Bergman makes no mention of grizzlies feeding on roots, so perhaps in McKinley catkin feeding is replaced largely by rooting. However, it would not be surprising to find bears feeding extensively on catkins in early spring in years of heavy snowfall.
Mushrooms: No mushrooms were found eaten in McKinley National Park by grizzlies. but, they are plentiful and probably are eaten occasionally. O. J. Murie found mushrooms in 8 of 42 scats he examined in Yellowstone National Park. The percentage present varied from a trace to 100%. Mrs. Ruth Onthank wrote me that she often had seen coral mushroom (Clavaria) dug out before it could break through to the surface, and signs indicated that black bears had been feeding on them. In France, of course, pigs feed extensively on the subterranean truffle.
Spruce Cones: I have found spruce cone remains in only one dropping in the park (Murie 1944). In Yellowstone and Teton National Parks the cones of whitebark pine (Pinus albicaulis) are eaten by grizzlies and black bears. The nuts in the cones of spruce available in McKinley National Park probably are too small to be sought after. If the cones were palatable, they would be abundant when there is a good cone crop, because in those years red squirrels collect large caches of them on top of the ground in autumn.
Blueberry (Vaccinium uliginosum): Grizzlies begin feeding on blueberries before the fruits are fully ripe. At the higher elevations, from 2,000 to 4,000 feet, feeding usually begins in the last half of July. The earliest record I have is 12 July, when blueberry was the principal component of a fresh dropping. Bears bite at the low bushes in much the same manner as they graze on grass, stripping leaves and berries. Occasionally, a paw is used to raise a heavily laden branch to bite more easily at the fruit.
Blueberry bushes, growing a foot or two tall, are abundant and distributed widely. The crop varies from year to year, but at some lower elevations the berry crop seems to be uniformly good. The bears seek out the best patches and for hours on end bite vigorously and rapidly at the bushes.
I have witnessed only a few poor berry crops in McKinley National Park. In 1963 all species of berries eaten by bears were scarce in most localities and not abundant anywhere. Various reports indicate that the berry crop was substandard in much of Alaska that year. Lateness of spring may have accounted for this crop failure. In 1964 and 1965 the overall berry crop was again below standard; poor in higher elevations and plentiful only in spots at lower elevations. Crowberries were plentiful, however, and bears fed heavily on them. Of the 143 scats in which blueberry was found, 31 contained only blueberry.
Crowberry (Empetrum nigrum): Crowberry is distributed widely over the park, growing in the woods and open country and far up the slopes. The crop is usually excellent and bears eat great quantities of it. This species vies with blueberries and buffaloberry in popularity, and because the berries winter well, it supplements the spring diet of roots. I often have watched bears feeding on crowberries in May and June. Some pass through the bear's digestive tract unbroken and others are only crushed. Of the 254 scats which contained crowberry, 138 had only crowberry.
Buffaloberry (Shepherdia canadensis): Buffaloberry grows on rather gravelly terrain. It is found on lower slopes, washes, and old river bars. The berries usually are abundant and an important source of food. The berries become available during the latter half of July; I have seen bears feeding on them as early as 16 July. Many leaves are eaten with the fruit, no doubt inadvertently. At times mountain sheep compete for some of the berries but not seriously. In 1961, during a September migration, about 130 sheep stopped as they were crossing the river from Divide Mountain and fed on a bar along the Toklat River. A number of sheep fed on buffaloberry, depleting slightly the supply in this restricted area. Of the 87 scats that contained this species, 38 contained only buffaloberry.
Silverberry (Eleagnus commutata): Over most of the park silverberry is not available. I saw two small patches near Igloo Creek, and noted flowers on the bushes but no berries. Down the Toklat River, near the park boundary, I have seen several bushes and it is likely that at these lower elevations the plants bear fruit. The mealy berries remain on the bushes all winter. Coyotes in Grand Teton National Park sometimes feed on them in winter.
Cranberry (Vaccinium vitis-idaea): Cranberry is distributed widely and the plants bear heavily. The berries are not eaten much in late summer or autumn, but the grizzlies consume some in the following spring, during May and early June. On 20 June 1955 fresh scat from a yearling contained chiefly cranberry, and on 20 May 1962 a fresh scat left by a large male contained mostly the hair of mountain sheep but also about 600 cranberries. In 1962 a few cranberries were seen in fresh droppings as late as 21 and 25 June.
Arctostaphylus alpina and Arctostaphylus rubra: The large, black berries of A. alpina that grow in the open country, and the red berries of A. rubra that grow in moist areas and in woods are eaten occasionally. However, they are so scattered on the plants that they are not eaten in quantity in the park. On 7 August 1926, O. J. Murie found a number of the red berries in the stomach of a black bear killed on Old Crow River, and in the same locality berries were found in many droppings of the black bear.
Rose (Rosa acicularis): I have not witnessed grizzlies eating rose hips, but in low country where the rose is plentiful it probably does enter the diet. Along the Porcupine River, O. J. Murie found that black bears eat rose berries, and I have seen them eaten in Yellowstone National Park by black bears. In McKinley National Park the rose would not be an important food item.
Miscellaneous Foods: Various other plant foods are tasted occasionally but are unimportant. I have seen Artemisia arctica, Sanguisorba sitchense, Polemonium sp., Heracleum sp., and Angelica sp. tasted. On one occasion it appeared that the underground stems and buds of coltsfoot (Petasites) had been eaten.
Figures 34-39 depict various plants used for food by bears.
Caribou: At all times these animals are a potential source of carrion (discussed under "Carrion"). During the calving season some calves are captured by bears that live in calving areas. (The mammal species that are food for grizzlies are listed here, but also are discussed in detail in the sections dealing with grizzly relationships and with carrion.)
Moose: Adult moose furnish a certain amount of carrion, and a few calves are obtained in the calving season.
Mountain Sheep: Sheep eaten by grizzlies usually is carrion. It is possible that a sheep may be captured occasionally when migrating across stretches of flat country, although I have no record of such an occurrence. Occasionally a bear has been seen chasing migrating sheep in the Toklat River area, but the sheep escaped. Once a migrating ewe was in danger when crossing a late spring snowfield, but she managed to cross without being overtaken by the pursuing grizzly. On one occasion a yearling was captured. Sheep are a sporadic source of food.
Shed Moose Antler: On 8 August an employee of the National Park Service saw a large bull moose drop an antler on Sable Pass. Later, I saw a bull with only one antler; it was an animal that had spent the summer in the area. When I found the antler, a few days after it was dropped, a bear had eaten the soft tips and the velvet. The antler had been infected and necrosed just above the pedicel, causing it to drop off. On two occasions I have seen cubs chewing on a caribou antler, but I think this was done in the spirit of play.
Marmot: The marmot apparently is seldom captured by the grizzly. A marmot den usually is located in rocks or cliffs where bears cannot dig it out. It would seem that if marmots dug dens away from rocks, bears would capture them more frequently.
Ground squirrel: The ground squirrel makes up a small but perhaps important part of the grizzly diet. It is eaten at all seasons, and may be hunted methodically.
Voles and Lemmings: Meadow mice and lemmings furnish the bears with a taste of meat. They are not particularly sought after, but when they are abundant, bears may spend some time feeding on them.
Beaver: Bears probably seldom capture beaver but on occasion they may discover one that is too far from a pond to escape. On 30 May 1941 a female beaver containing two large embryos was found dead on the shore of a creek near Wonder Lake. It was potential carrion.
One year in late June, Mrs. Elizabeth Berry saw a bear working at something on the shore of Wonder Lake. When the bear left, a beaver carcass was discovered frozen into the ice that filled a burrow. The grizzly returned later and retrieved the carcass.
Grizzly Carrion: I was unable to determine the extent to which grizzlies will feed on grizzly carrion, and possibly it varies with the individual. I have driven sled dogs that exhibited individual variation in their tastes for dog meat. Some ate it raw, whereas others, although hungry, would not eat it uncooked. A female grizzly that killed two spring cubs did not feed on the carcasses, although, at the time, she apparently was too concerned over the safety of her own cubs to be interested in food. However, I have seen two carcasses that were fed upon by grizzlies.
Insects: In McKinley National Park few insects are available for food. A few wasps are eaten; about a dozen were found in one scat and two or three in another. Apparently the ground nests had been dug out. O. J. Murie found two bees in a scat in the Sheenjek River area and some in a scat collected in Yellowstone National Park.
On some grizzly ranges farther south, insects are more important in the diet. O. J. Murie found ants in 10 of 42 scats collected in Yellowstone National Park.
In the Mission Range, Montana, a number of bears were observed turning over rocks above timber, at an elevation of about 10,000 feet (Chapman et al. 1955). These authors found large aggregations of ladybird beetles (Coccinella) under rocks in the area where bears were feeding. Some years later, one of the authors collected and examined 15 grizzly scats in the area at an elevation of 8,000 to 9,000 feet. Nine of the droppings consisted almost entirely of moth (Chorizagrostid auxiliaris) remains, the adult stage of the army cutworm. Ladybird beetles were not found in the area at the time the droppings were collected. The authors stated that the moths apparently were captured under rocks where they gathered during the summer.
In Yellowstone National Park I noted black bears on the summer buffalo range feeding on grasshoppers and Mormon crickets. The bears had turned over hundreds of buffalo chips to find these insects. Of 64 scats collected, 61 contained Mormon crickets and grasshoppers, mostly the former (Murie 1937). If grizzlies had been present, no doubt they also would have fed on these insects.
Data from Scat Examinations
The food habits of grizzlies in McKinley National Park can be determined satisfactorily by watching bears feeding and checking feeding signs. Additional data were secured by examining scats and estimating the approximate proportions of various food items. Since the scats usually could be dated fairly accurately, the data in Table 8 are segregated into time periods, indicating seasonal food habits. The number of scats in which various food items occur depends to a considerable extent on how much time was spent collecting in the different habitats, and some items, such as Boykinia and mice, probably are underrepresented in this analysis. Moose are not recorded in Table 8, yet we know that it was eaten. Moreover, I only identified some of the herbaceous material, and sedges were included with grass. The importance of various herbaceous species is cited in the annotated list of food species (Figs. 40, 41).
The proportion in which various food items were represented in the scats were calculated, but this classification, usually done in the field, was quite rough except for those scats that contained only a single item. I have indicated in Table 8 (numbers in parentheses) the number of occurrences in each category that represented 50 to 100 percent of the scat.
During spring, the chief food is the root of the peavine, and bears can be seen seeking these roots on old river bars and ridge slopes, rooting areas well known to them from previous years. This root diet is supplemented occasionally with crowberry and cranberry, berries that survive the winter fairly well; blueberries also show up in a few spring scats. For those bears living on migration routes where caribou calves are born, the calves may be an important food item in part of May and early June. A few moose calves also are secured at these times. When green vegetation is available, the diet of spring roots is dropped.
Green grass may be available in late May or early June, but in some years, in places such as Sable Pass where the season is late, this food may not be available in quantity until the middle of June. This change in diet is sought eagerly, and bears feed avidly on the first green shoots. Not all bears turn to green grass at the same time, however, even in the same general area; some continue feeding on roots after others have found and are feeding on grass. The first grass to appear in many places is a tall species, Calamagrostis canadensis. It apparently is relished when young and the only green food available, but when horsetail, certain herbaceous species, and their favorite grass, Arctagrostis, appear, the bears turn to them. The palatable grasses and herbs generally grow in moist hollows and draws, in hummocky areas, and along small streams. One of the heavily grazed legumes is abundant on old river bars. Grass, herbs, and horsetail, the staff of life during much of June and July, are attractive to bears until berries begin to ripen.
When berries (chiefly blueberry, crowberry, and buffaloberry) ripen, they are the favorite food. Green grasses and herbs are eaten after berries enter the diet but usually are second choice. Bears devote most of their time to berries, and a majority of the droppings contain only these fruits. Blueberry bushes are dispersed widely in extensive stands. They are found in valleys, on flats, and on lower ridge slopes. Another important berry, crowberry, also is dispersed widely over the landscape, and these evergreen, trailing plants are loaded with juicy, black berries. The bitter, red buffaloberry also is plentiful and usually produces a large crop. Its distribution is more localized than blueberry and crowberry, being usually found on old gravel bars, on dry benches near streams, and scattered on lower ridge slopes. These three species comprise the bulk of the berry diet. Cranberry is abundant but is not eaten extensively. Arctostaphylus berries are eaten but are not abundant enough on the plants to be much sought after, although I have found a few scats containing many of these berries. Currants, found commonly in alder thickets, probably are eaten.
In late August and September some bears return again to roots. In September, in poor berry years, I have seen some bears feeding on roots all day for several days while others persisted in seeking berries. In those years when the berry crop is poor, green grasses, sedges. and herbs may remain important through August and into early September. There are individual differences in food habits, especially during transition periods, due in part to the food supply where a particular bear is foraging. Some bears that summer at higher elevations regularly seek lower country when the berry season starts, but others remain where they are.
Ground squirrels are eaten at all seasons, but particularly in late summer and fall. At any season when bears are abroad one may chance to see a bear working industriously to dig out a ground squirrel, a task that varies in duration and may be unsuccessful. In years when fieldmice or lemmings are abundant, some bears may be seen feeding extensively on them.
Carrion always is attractive to meat-hungry bears and is available quite often. Thus, it can be seen that the diets of grizzly bears are varied.
Carrion and Caching
Carrion is attractive to many animals and especially to meat-loving grizzlies. The important sources of carrion in the park are caribou, moose, and sheep. Sooner or later individuals of these species succumb to disease, predation, or old age (directly or indirectly) and become sources of food. The magpie, camp robber, golden eagle, wolf, fox, lynx, wolverine, and grizzly all seek their full share. If the direction of the breeze is favorable, the scented message may reach the grizzly from afar, and he may be the first to reach a carcass. If he is not so fortunate, the carcass may already be devoured by the competition when he reaches it. Sometimes a carcass is not discovered for several days, but the state of decay is immaterial to a hungry grizzly.
The supply of carrion in a bear's home range varies from year to year, and these blessings are not distributed uniformly. Some grizzlies may be located favorably to procure carrion because of the prevalence of large herbivores on their range. For the most part carrion represents only a special treat.
In August 1962 several bears in country I was frequenting were especially fortunate in regard to carrion. These bears were living on the migration route of the caribou and, although the main caribou herds had migrated westward, a number of scattered caribou bands still remained. During this August I knew of six old caribou bulls that had died, and the bears probably knew of others. One old bull, apparently ailing, was killed by a lone wolf, but the bears did not recognize any special wolf rights and helped themselves. One-half mile away another old bull caribou carcass was untouched for a few days. This bull was in good flesh but it apparently had died from a disease. The bears, wolves, and others had devoured all evidence of the other four dead bulls by the time I examined them, but all had reached a ripe old age.
After eating to his capacity, a grizzly usually covers the carcass with sod and debris. He paws the debris loose first with one paw then the other, then rakes it back toward the carcass. Sometimes, after loosening and pawing debris with his forepaws, he may scrape it farther back with a few hind-foot strokes. It is a lazy process, undertaken after a huge meal. After the carcass is well covered, the raking may be resumed at intervals as though some satisfaction is connected with this activity. When the carcass is heaped over with scrapings, the bear may rest nearby, or he may lie on top of the cache as though proclaiming his proprietorship. Sometimes after covering a carcass the bear may move off a short distance to rest. If one comes upon a bear cache, the bear probably is resting nearby or has fled at one's approach. Even after only bones and hide are left, the carcass may be visited occasionally. Once a mother followed by two yearlings, after feeding, retired to cliffs one-quarter mile away from the carcass, but the next day after feeding she rested near the carcass.
A bear may roll on an old carcass just as a fox or dog will. One day I watched a 3-year-old bear investigating an old caribou carcass long since salvaged. Before leaving, the bear rolled on the remaining pieces of hide and bone for 3 minutes. Then he walked to a little creek, waded into a deep hole, and lay down so that the water covered him except for his head and shoulder hump. Bears often lie in water in this manner, apparently to cool off, so I doubt that he was bathing or trying to wash away odors.
Usually no contact occurs between a bear at a cache and an intruder. Superiority seems to be recognized. Either the bear at the cache will retreat or, if he is bigger or perhaps more aggressive, chase the intruder. Very likely the bears on a range are well acquainted and do not need to re-evaluate status at each meeting. Occasionally an altercation takes place, because an intruding bear, even if small, is attracted strongly by carrion and will make some effort to partake.
During the winter when bears have tucked themselves snugly into dens, much carrion becomes available. Most winter carrion is consumed by wolves, wolverines, and foxes. But when bears first emerge in early spring, they salvage some of the leavings. They may find a sheep skull they can crush to retrieve the brain or bits of nourishment on bones and hide. Sometimes winter kills are covered by snow and become available when thawing begins and bears are abroad again. In the winter of 1962-63 a number of caribou succumbed on a mountain slope near Deniki Lake, just east of the park. Apparently they were killed in an avalanche. Bears fed on the carcasses throughout much of the summer. At least six or seven bears, including cubs, were attracted to the slope and were observed over a period of several weeks by Bill Nancarrow and Mr. and Mrs. William Berry. As summer progressed, the snow melted and additional animals were uncovered.
The following incidents, a few of many I have observed involving caching behavior of grizzlies and other activities at carrion, show more fully the ways of bears with carrion.
A Mother With Three Cubs Concerned About Her Caches
On 24 August 1906, Sheldon (1930) describes a mother with three cubs that hurried to the carcass of one of seven rams Sheldon had shot and began:
Bull Moose Becomes Carrion
On 16 November 1949 a bull moose, carrying a huge set of antlers, was resting on a willow patch near Savage River. Looking at him through field glasses, I noticed a whiteness on his eyes. When he stood up and browsed on willow, he was inept and groping and when he walked, each front foot was lifted high and moved forward uncertainly as though feeling for the ground.
There were scars about his face that may have been made by antler points, suggesting that the bull had been blinded in a fight during the rut. As he faced my companion and me, his ears were laid back as they are when a moose is angry; he licked his lips, and saliva drooled from his mouth.
This was a last stand, not against a predator, but against an infirmity. Until recently, he was a monarch whose antler spread was great and who could hold his own against a wolf pack or grizzly bears. It was sad to contemplate. Now he lived in a world of darkness, feeling his way and stumbling against boulders. I wondered if wolves would notice his condition and how his head jerked when an antler struck unexpectedly against a spruce or willow limb. It would have been an act of mercy to kill him. However, he was in the middle of an extensive area of willows and did not lack nourishment.
The following day we returned to the bull to take pictures. He was lying down about 400 yards from where we had left him. During the interim he had lost an antler, which we found. The one he still carried had an abnormally located prong, and we found it later after it had been shed. One antler weighed 25 pounds, the other 24 pounds; we estimated that the antler spread was at least 70 inches.
The bull was still alive on 19 January, but on 15 February we found his carcass and judged he had been dead 3 or 4 days. The temperature was about -20°F and the carcass was frozen. In time, successive snowfalls buried it. On 28 February the carcass was visited by a wolverine, a fox, and ravens which had fed on the neck. During the next month and a half, the above three species and a black wolf visited the carcass regularly. If the carcass had been fresh, it would have disappeared in a matter of days, but being frozen solidly and covered with packed snow, the flesh could be removed only by laborious gnawing and no parts could be carried away for caching. Enough remnants still were available after the middle of April to interest a grizzly that was abroad early and wandering over the country looking for food.
That same spring, on 11 May, I saw another large bull moose that had survived the winter but would soon become carrion. He was extremely thin, and his poor condition was further evident from the fact that no new growth of antlers was noticeable. In healthy bulls at this time new antlers had attained a length of 10 or 12 inches.
Lone Bear Discovers a Carcass
About 9 a.m. on a warm day in July, I watched a lone grizzly with nose raised, ears cocked forward, traveling into the wind along a hillside on a contour. He stopped a few times to look ahead. He was approaching the carcass of an old caribou bull. The bear's behavior suggested that he was about to make a discovery. One hundred yards from the carcass he stopped to look and test the breeze. From there he moved more eagerly, and nearer to the carcass he found a leg bone with most of the meat removed. After feeding on it for a few minutes, he walked down a bank, which lay along a little stream, to the carcass and managed to pull it part way up the bank. He started feeding on the rib section, swallowing large pieces but chewing little. In half an hour he moved off a few yards and scratched himself thoroughly with front and hind paws. He resumed his feeding for a time, then drank briefly at the stream. He rested for 15 minutes, then began pawing the sod, sending the chunks in the general direction of the carcass. After a few minutes, he lay down with ears cocked and at short intervals raised his head to look around.
At 10:30 a.m. he resumed feeding, and in 40 minutes was again scraping sod toward the carcass. At 11:20 a.m. he had another drink, then alternated resting and pawing sod and debris toward and over the carcass from 12 or more feet away. Once he trotted over to chase away two magpies. At 12:40 p.m. and again at 1:20 p.m. he took another drink. At 3:30 p.m. he uncovered part of the carcass and ate. By 4:15 p.m. he had pulled the carcass farther up the bank, and a little later he started covering it with the debris he had pawed loose earlier.
When I saw the scene the next morning, the carcass was well covered and only the antlers protruded. The bear was engaged part of the time in loosening more sod and pawing it over the carcass.
In the afternoon a slightly smaller bear intruded and was charged and chased for some distance. Later a second bear was reported to have crossed the stream three times, each time making contact with the bear in possession and each time being repulsed.
Bears Feed on Two Sheep
On the afternoon of 22 June 1965, a dark mother and a 2-year-old cub were discovered as they fed on a carcass lying in a short ravine not far from Toklat River. The carcass had been covered with debris by the bears, and was partially uncovered where the bears fed. Not enough of the carcass showed for identification. After feeding to a state of satiety, the mother pawed more debris over the cache, then collapsed on the heap as though too full to stand. A little later the cub, who had been feeding at one edge of the heap, approached the mother, pushed his head under her neck and chest and succeeded in promoting a nursing.
The following morning (23 June) the family was at the carcass when I arrived at 7 a.m. They fed, rested, and nursed until 4 p.m., when they moved into the willow brush and fed for an hour on horsetail before climbing a slope to rest. As they lay on the hillside some 150 or 200 yards from the carcass, a blond mother followed by a blond yearling emerged from the heavy willow brush and gleaned what they could from the remains. Two hours later they moved off and lay down 50 yards away.
On the morning of 24 June a magpie was foraging on the cache, finding crumbs too small to be noticed by bears. Fifteen minutes later the dark mother and her 2-year-old cub emerged from the willows for another taste. The cub jerked at a part hidden from its view and exposed the skull of a ram with large horns. Later, when I examined this head, I learned that the carcass was that of a ten-year-old ram. Apparently, this old, vulnerable animal had wandered onto gentle terrain in search of green vegetation, been surprised while away from friendly cliffs, and been killed by wolves whose tracks were at the carcass.
One-half hour after the family arrived at the carcass, a large male bear came up a small creek bed and turned into the short ravine where the family was feeding. The frightened family departed and the male took over. He found little attraction at the cache and after stirring around for 15 minutes, while a pair of shrikes snapped their beaks to demonstrate their annoyance, he returned to the brushy hillside. Later, I caught a glimpse of the blond mother and yearling in the tall willows near the cache, but they moved away to continue grazing on horsetail.
Before arriving at the carcass of the old ram on 23 June, I had discovered another carcass of a 4-year-old ram one-quarter mile or less to the south. Tracks crossing the road above this carcass showed deep tracks made by the ram, and deep imprints of a wolf. Apparently, a wolf had chased the ram and overtaken it a few yards below the road. The carcass was only 60 yards down the slope and had been dragged part of this distance. Most of it had been devoured. Earlier that morning, three wolves had been reported near the carcass. When the stomach contents were examined, I remarked to my companion that the food was masticated poorly. Many leaves of willows, including Salix reticulata, and leaves of anemone were intact; there were even clusters of willow leaves. This suggested that the ram had difficulty chewing, and when I examined the teeth, I found them badly ulcerated and worn on a slant. One molar had dropped out and another was loose in its ulcerated socket. On one side of the lower jaw an ulceration in the bone contained about a tablespoonful of pus. This was another classic example of a weakened sheep, in this case from disease, being eliminated by a predator.
The carcass of this 4-year-old ram was visited briefly by three wolves on 25 June but so far as I knew was not discovered by bears until the 26th, about 3 days after it was killed. On the morning of the 26th I saw the mother and 2-year-old cub 100 yards from the ram. The mother was moving about with nose to the ground. After about 5 minutes, her searching brought her downwind from the carcass and she walked directly to it. The mother bear fed for about 45 minutes. The cub spent most of the time playing with a piece of sheep hide. There was little left of the carcass except pieces of hide and bones. The mother did not bother to cover it with soil or debris as she probably would have done if more had remained. After a nursing, the family departed. This carcass was discovered by the bears too late for it to benefit them.
One day during the period when the bears were feeding on the old ram, a lone ram was seen on a low hill a little to the east. For 10 minutes he surveyed the country, as sheep are wont to do, before migrating across low and, from his standpoint, dangerous country. The ram then walked down the slope, followed a ridge to the stream bottom, climbed out on the tundra, and started moving across more gentle terrain. Along the way he startled small groups of caribou who were unaccustomed to seeing this white animal away from steep terrain and cliffs. A group of 30 caribou stampeded and circled back to gaze at the unperturbed ram. I watched the ram cross to safe cliffs. A wolf had been seen earlier in the day in the general area but apparently he had moved on. If a wolf had discovered this crossing, the ram might have become another bear cache. Crossings usually are safe because the low country is scrutinized carefully for some time before risking the crossing, but this illustrates the circumstances that might create carrion for bears.
The Bear in Possession Chases Away Smaller Bear
On 6 September 1959 an adult bear had covered a sheep carcass with sod and vegetation at the edge of a flat near Little Stony Creek. When I saw him, he was still pawing debris over the carcass, working slowly, as though disinclined to give up a pleasant activity. One or both of the forepaws were used to loosen the sod and scrape it and other debris toward the carcass. Sometimes the hindfeet also were used to push debris toward the carcass. When he stopped pawing, he lay on the heaped-up mound, the owner in possession. Later, he continued raking vegetation from all sides, forming a 40 foot circle around the carcass. Later still, the possessor galloped after a young bear that was about 150 yards away; chaser and chased both put on speed, and the young bear escaped easily. As the bigger bear walked back toward the carcass the intruder followed, sure of his ability to escape. Shortly before the owner returned to the cache, another chase took place and after escaping, the intruder lay down for a time before wandering away.
The following day very little was left of the carcass. The larger bear was gone and the small one was pawing about in the cache looking for scraps. He left with what remained of the head of the sheep, but dropped it on the slope so that I was able to retrieve it and learn that the dead sheep was a 10-year-old ewe. The cache area made a conspicuous dark spot on the flat.
Carcass at Little Stony Creek
Early in the afternoon of 7 September 1964, an adult female bear was seen stretched out a few feet from the carcass of a caribou bull. She lay on her side, occasionally raising her head to look around, and once stretching a foreleg into the air. After a time, she stood up to urinate and leave a scat. She surveyed the surroundings while standing on the cache, pawed a little more debris over it, walked away about one-quarter mile, and rested on a slope. An hour later she was roused by a young caribou bull, and stood up. Without hesitation, she walked rapidly toward the carcass. After pawing aside debris, she fed, pulling loose long stringy pieces. In a few minutes she pawed more loose debris over the cache and walked away again, passed the spot where she had been resting, and continued until she disappeared over a rise. The cache was about 15 feet long and 12 feet wide. I estimated about 25 bushels of sod and debris had been pawed over the carcass. The material had been scraped into an area about 30 feet across. The worn condition of the teeth indicated that the carcass was that of a very old bull (Fig. 42).
A Cache Unprotected
On 26 August 1956, in the Wonder Lake area just outside the park boundary, while searching for a caribou that had been shot and abandoned by a hunter, three companions and I came upon a fresh mound of vegetation consisting chiefly of sphagnum moss. The caribou carcass had been found by a bear. After a feast, the grizzly had covered the carcass with tundra moss. The cache in this case was not at all conspicuous, for the moss covering was green and brown like the surrounding ground cover. A few days later, the carcass had been devoured. It is likely that this bear had not remained at the cache because of the human disturbances in the area.
Grizzly Feeding on Diseased Sheep
On the morning of 11 May 1964, some distance up a slope of Savage Canyon, a bear was pawing debris slowly over a sheep carcass. When I passed by 6 hours later, the bear was sitting on his haunches feeding on the carcass. On the following day the bear was seen lying beside the carcass, waiting for his hunger to return or at least for stomach space. A few days later at the site I found the sheep's hide, with four legs attached. Scattered about was much loose sod and debris which the bear had used to cover the carcass. The horns, detached from the skull but still attached to the hide, showed that the sheep was a 6-year-old ewe. The teeth were in bad condition. Two of the molariform teeth had been missing for some time, resulting in very long, little-worn teeth opposite the cavity of the missing teeth. The jawbone below the missing teeth was swollen and porous, the necrosis no doubt having caused the loss of the two teeth. The upper molars were worn down at an angle. Three incisors on one side had been missing for some time. One horn, worn smooth, had been broken off near the base, suggesting an old accident. A ewe with a bad mouth that no doubt affected her health had succumbed. The hide was bloody, suggesting that she might have been killed by a wolf or bear.
Prolonged Visitation to a Carcass
On 18 June 1961 a mother bear and yearling were feeding on the carcass of an old bull caribou that had become entangled in some wires left behind when the telephone line was dismantled. Two foxes were also present, waiting for an opportunity to feed. The following day I saw this family leave the carcass at 2 p.m., and cross a patch of overflow ice on the creek bottom before entering an extensive patch of dense willow. After their departure, Short-billed Gulls dived at a Golden Eagle perched on a ridge overlooking the carcass. At 3:15 p.m. a wolverine arrived and fed for 5 minutes. At 4 p.m. the mother and yearling returned and the mother fed for 35 minutes. She then pawed moss and other loose vegetation over part of the carcass, fed on a detached piece for 5 minutes, and lay down with her cub a few yards away.
For the next few days I saw no bears at the carcass, but a mother and two cubs were reported at the carcass on 24 June. In the morning of 25 June a large male had taken charge. He had covered the carcass with more sod and vegetation and rested on his side on top of the heap. Once as I watched, he raised his head lazily for a casual look, then relaxed, dropping his head to the mound. His sides moved up and down as he breathed (33-35 breaths per minute). Occasionally he adjusted his weight for more comfort. Toward the middle of the morning he fed drowsily on a jawbone. When I passed by at 7:30 p.m. he was still resting on the cache. On the 26th and 27th he continued to feed and sleep on the carcass. On the morning of the 28th I saw him climb a slope and disappear over the top. That evening a mother with two 2-year-olds was at the carcass, and on 3 July this family was seen leaving it. Only bones and a little hide remained. I thought the carcass was no longer an attraction, but on 18 July I happened to see a wolverine leaving it, dragging a leg bone, and on 4 August a mother and two spring cubs discovered the remains. She was pulling pieces of tendon from the long bones, tough tendons 15 or 18 inches long, which she swallowed without chewing.
Three bear families, a big male bear, two foxes, a wolverine, an eagle, gulls, and perhaps others were attracted to this carcass. Ordinarily, such an attraction lasts only a few days because it is finished in that length of time. I do not know why this one attracted attention for so long unless the wire entanglement caused some difficulty. After the big male grizzly left, I expect there was still an attractive odor, and small bits of dry flesh clinging to the entangled skull.
Lone Bear Dispossessed
One morning (30 June 1964) when I was studying vegetation on Sable Pass, I saw 50 or more caribou bulls, old and young, trotting past a young blond bear, about 3 years old. Two other bands were moving by him in such manner that for a few moments they were passing on three sides. Standing in the midst of these caribou movements the bear seemed uncertain whether he should become frightened. Finally, he made a short run, stopped, and then regained some composure.
In the afternoon when I returned to the pass, I saw this bear near where he had been in the morning, tugging at the half-eaten carcass of an adult caribou. Apparently it had been there in the morning, but it lay in such a way that I easily could have missed seeing it. The bear was pulling on the carcass as though trying to drag it up the slope. Later he managed to drag it about 25 yards down the rather steep slope. Three Golden Eagles were perched 50 yards away on the ground on the far side of the gully. One left, but the other two stayed for the half hour that I watched.
In the evening when I returned to the pass, the bear was pawing sod over the carcass. Two eagles were perched 100 years away. Soon the bear walked down to where the slope flattened out and drank at three small pools. In 5 minutes the bear started back toward his cache, galloping for a few yards, and was soon tugging halfheartedly at an exposed part. One eagle flew away. A mother with two spring cubs was on the west side of the pass. She had been in the area all day, and two lone bears also had been grazing on that side of the pass. They all were unaware of the banquet they were missing.
At 4:25 a.m. the following morning the mother bear with the two spring cubs had found the carcass and were resting; an eagle was perched 100 yards away; and the blond bear was grazing 150 yards down the slope. In 5 minutes the eagle took wing and I heard him calling as he flapped away. It would pay him to look for a ground squirrel rather than watch bears snoozing at a carcass. An hour later the family and the small blond bear were resting. Mew Gulls were in the area calling and again I heard the "wha-wha-wha" of the Golden Eagle. A few flakes of snow were in the air. By 6:40 a.m. a mixture of snow and rain was falling. The mother stirred, stood up, and pawed more sod on the cache. A little later the mother and cubs fed briefly and then all lay down. The snow was whitening the landscape.
On 2 July the carcass had been dragged down the slope another 50 yards where it had again been covered with sod. By evening the carcass was desertedapparently all available flesh had been eaten. On 3 July the family and a lone bear were in the area but were not attracted to the carcass. On 4 July two gray wolves passed by while a small lone bear was at the cache. It chased one of the wolves that was carrying a leg bone as it disappeared over the skyline. Only odoriferous bones and hide remained.
Male Grizzly Discovers Moose Carcass
On the morning of 21 May 1963 a Mew Gull was diving at a Golden Eagle that was feeding on the carcass of an adult moose lying in the edge of one of the channels of the Teklanika River. In the afternoon I saw a chocolate-colored bear, a large male, at the carcass. He was biting the carcass and discarding mouthfuls of hair. A little later he removed and discarded some of the intestines. After feeding for 15 minutes, he pulled at the carcass, dragging it in the direction of the woods on the far side of the broad river bar. Clamping his jaws on the carcass, he braced all four legs and pulled backward, moving the carcass a few inches at a time. Once he rolled it over, and once turned it over end for end. He grasped the carcass at various places, sometimes pulling on a leg. At intervals he stood panting with mouth open. After dragging the carcass about 75 yards, halfway to the woods, he stopped his labors, stood briefly, and walked into the spruce woods, probably to rest.
The following morning the big male was lying on top of the moose carcass, which was still out on the river bar. No attempt had been made to cover it with gravel (the only material at hand). By early afternoon the carcass had been dragged just inside the spruce woods, and the male was lying on it. Out on the bar a small blond bear was nosing the spot where the carcass had been lying and the trail made when it had been dragged. The male saw the blond bear, and with long, slow strides came out on the bar a few yards, stood briefly watching the small bear walk away, then returned to his prize.
In the evening I found this male bear resting again on top of the carcass. A small dark bear moved from the bar into the woods a little distance north of the carcass. About 1 mile to the north the small blond bear was seen walking rapidly along the edge of the woods toward the carcass. As it came nearer, it raised its muzzle repeatedly to test the breeze. It walked into the woods and chased the small, dark bear, both disappearing among spruces. The male, hearing them, also disappeared into the spruces. The young bears reappeared on the bar some distance south of the carcass, the blond one galloping after the small, dark one, who continued northward for a mile.
The blond bear moved cautiously to the carcass, became nervous, and jumped away several yards. He circled into the woods and again approached the carcass, biting at it, then jumping away nervously. Before he could approach again, the big male returned and the blond disappeared in the woods. The male lay down on the carcass. I saw him on the carcass the next morning, but I could not find him a few days later.
Carrion in any form, fresh or ancient, is a special "delicacy" for a grizzly, although not a major food source. A large carcass may attract several bears over a short period of time, bringing them into closer contact than is usual. At most times, little overt strife results; larger bears have priority and others partake as temporary absence of a more dominant bear permits.
Last Updated: 06-Dec-2007