Chapter 7: Coastal Brown Bear

True bears, by Fred Kurt, Bernhard Grzimek and Victor Zhiwotschenko, in Grzimeks Enzyclopädie, volume 3 (1988) Munich

Winter sleep and winter den

"Only in recent time, American researchers, such as John J. Craighead and G. Edgar Folk, have studied the body economy of the polar bear, baribal (black bear) and grizzly bear, while resting in winter. Their findings were almost sensational: 'We do believe that the winter sleep of the bears is much more perfect than that of small mammals ', writes Folk, after he had studied them for eight years. Thus he stands contrary to the earlier school opinion, which stated: 'In the winter the bear falls into a sort of half-sleep, at normal body temperature. Thus he is able to leave his den at any time, when his safety is threatened, in contrast to the other animals, which sleep in winter.' But that is not true. The bear, which sleeps in winter, will wake up, when he is heavily disturbed, in contrast to the ground-hog. But when the bear is in a deep sleep, its body economy is very much reduced. It seems, as if he were closer to death than to life.

When the grizzly bear sleeps in winter, for example, its pulse of the usual 70 heart beats per minute slows down to half as many. Baribals [black bears] lower their blood temperature during their winter sleep by at least one degree, from about 38° to 37° C. And also: The bear, which sleeps in winter, during at least four and one-half months, do neither drink nor eat. During this time they do not excrete either urine or excrement. So it will not surprise us, that at the end of its winter-sleep, the bear will have lost a seventh up to a quarter of its body weight, even though its body economy was strongly reduced. That is why the bear, which sleeps in winter, uses only half as much oxygen, than in the time, when he is awake.

One may ask oneself, why it took so long, to discover this that the bears do sleep in winter. Because thousands of them have lived and are still living in zoological gardens. Here, however, the bears do not sleep in winter. In their stables it is too warm. And there they also feed them during the whole winter. The winter-sleep will only begin, when there is too little food and when the temperature falls below the freezing point. In this point bears differ from the Seven Sleepers. This rodent, which also sleeps during the winter, falls into a deep sleep independently of the temperature, when the days become shorter. Then he also sinks rapidly into its natural narcosis. Bears, however, need at least two weeks, to change their body.

Also the North American and Russian bears build and move into caves, when the winter approaches. They dig their winter dens usually into steep south-facing slopes. This is especially in arctic areas very important. Here the eternally frozen soil thaws up to a depth of two meters during the warm season. And on the steep rock slopes the melt-water flows off in the spring at once.

Harry V. Reynolds and his co-workers measured 56 caves of the powerful grizzly bears in northeast Alaska. The entrances to these impressive caves are a half up to three meters high and wide. The cave itself penetrates three to nine meters deep into the interior of the earth and widens at its end into a large hollow. At the floor of this hollow (cave), the bears have built a ‘bed’ from plant material. It has a diameter of about two meters and a height of 30 centimeters. There are not many places, where the grizzlies are able to build a winter-den. Often they are far away from their home range, where they live in summer. Reynolds measured the distances between their summer and winter homes. They lay three, 13 and even 55 kilometers apart.” (1988:480, 481).

"In Decembers and January the brown bear and black bear gives birth to its young. Usually twins are born, sometimes also one or three cubs and very rarely four or even five. We do know from the zoological gardens, that the bears do not have a specific rutting season and a time, in which they are pregnant. Brown and black bears pair themselves between May and July. Up to 16 mating between a pair on the same day were observed. This mating-game they may repeat during the following days.

Depending upon the authority, they are pregnant for six to seven or even six to nine months. Nevertheless, the cubs are all born at the same time. This is possible, because, when they mate in spring, before the pregnancy begins, because the fertilized egg will grow only up to the vesicle or hollow germ stage, the so-called blastula stage. Then it interrupts its growth and does not nestle down at once in the womb. This happens only at the end of the summer. Such a pregnancy, where the pregnancy is longer, than normal, because the germ does not grow for some time, occurs also in other mammals.

Young bears will spend, depending upon kind and habitat, the first one and a half to two and a half years with their mothers – or with another mother-bear, which also raises cubs, which are just as old. They have found out that especially among North American brown bears the mother bears do exchange their cubs, that they adopt strange cubs or that their own children will live with another mother." (1988:482)

"The bears will attack other bears in same way, as they will sometimes, if they are surprised, attack human beings. Sometimes, also the hunger will cause them to kill human beings. Such cases for instance the Russian bear researcher S. K. Ustinov reports from Irkutsk. In the area of Lake Baikal he investigated more than 70 cases, where bears had attacked human beings. 60 of these cases occurred in winter. 17 times the attacking bears killed the person. And five of their victims they ate up nearly completely. But this happens only, when there is not enough food. These bears, which do attack people, they call 'Shantuni’. These bears are so weak, that they are not able to survive a winter-hibernation." (1988:492)

Brown Bear (Ursus arctos)

"The best-known representative of the true bears is the brown bear. In many subspecies it has lived once in Europe, parts of North Africa, North and Central Asia and North America. In Eurasia its size increases from west to east. The smallest forms are the bears of the Alps (length 170 cm, weight 70 kg of adult male), the Abruzzi and Carpathian Mountains.... The bears of Scandinavia (220 cm, 250 kg, rarely up to 340 kg) are somewhat larger. The largest size reaches the Kamtchatka bear (Ursus arctos beringianus) in the east of Asia and the Kodiak bear (U. a. middendorffi) of Alaska. The grown males in both of these subspecies may reach sometimes an overall length of three meters, and a shoulder height 120 centimeters. But also the bears of the Ussuri, of the Yenisey and from the area of Lake Baikal do belong to the giants among the brown bears, which, by the way, are not always brown. Some subspecies are reddish-yellow, some have different shades of brown to black. There are silver-grey and pale isabella-colored brown bears. To the light-coloured bears of the Old World, for instance, do belong the Isabella brown bear (Ursus arctos isabellinus) from the Himalaya and the Syrian brown bear (U. a. syriacus). In North America the grizzly bear (U. a. horribilis), also known as the grey bear, may have many different shades of colour." (1988:493)

Coastal brown bear in Southwest Alaska, by Bernhard Grzimek

"My son Christian and I climb up onto a small hill beside the rapids of the McNeil River. It flows in a bay of the Aleutian Peninsula off the coast of southern Alaska. Here we see on the bank and on a rock in the middle of the rapids 17 the bears at the same time. Only ten meters away from us the next one is. The biologist Lee Miller has counted here once even 60 bears at the same time. Where else in the world do we still find this? Each year, from the beginning of July to the middle of August these brown and blond giants gather here. Then the Keta salmon come in large swarms from far away, from the Pacific Ocean. They swim up the short McNeil River, to spawn. Below the rapids, the salmon accumulate in groups of 100, sometimes over 1000 heads. There they wait, until they have become strong enough, to swim and to jump up the rapids between the rocks through the 200 meters of the fast, white foaming water. 

Here they will be able to catch enough fish! These giants are nearly all the time soaked to the skin. From time to time, one of them jumps head first or with its belly first into the ice-cold water. Other bears will stand for well over a quarter of an hour in this water, while only the upper part of their body or only their head will be above the water. They swim, with their head submerged, to recognize in the clear water the fish under the surface. Again and again one of them stands for half an hour so deep in the racing current that the water rushes against its chest; it constantly sprays up like a white bow wave. But they do not have much warming fat beneath their skin like the seals. This fat they want to store up now in summer. They can do that quite easily within these few weeks.

There are twenty fishing places at these rapids, which the bears prefer. And these the bears will occupy according to their rank. The best catching place of all is a rock in the middle in the river; closely beside it the salmon must struggle themselves up on the rock in the racing shallow water, to get over the rapids. So it is easy for the old bear man, standing on this rock, to catch them. We watch him from early morning to late evening. So we are able to find out, that he is able to catch seven to eight fish per hour, altogether 62 salmon per day. In the end he will eat only the best parts, finally nearly only caviar. The rest, the greedily waiting sea gulls and the bears of lower rank will get. Because those lower-ranking bears stand at less favourable places and are able to catch only one fish per hour.

We both wonder, on what the bears live here. There are no deer, mountain goats and mountain sheep in this Kamishak Bay. But bears are 'prey grippers', 'carnivores'. From what do these 50 to 60 brown bears live, which they have counted near the McNeil River, and the other 80 to 100, which also come here each year for some time? I pick up a heap of excrement, which lies on the bear paths. This excrement does not stink, it nearly look like a horse apple. So I break it apart and find out: It consists nearly only of blades of grass, bitten into short pieces. The brown bear, whether one calls him grizzly, Kodiak or something else, thus lives almost like a sheep from grass, horse-tail, pastinak, berries and the roots of many plants, if one does not include there the six weeks, during which they catch many salmon." (1988: 494-496)

Table, page 498: Brown bear: 150-780 kg body weight, hibernates in winter.

10. November 2003, 18, 59 o’clock. ARTE, Grizzly Giants, by Andreas Kieling. Andreas Kieling has filmed in Alaska during the last 11 years.

Coastal brown bear

"In central Alaska the grizzlies do not find much to eat. We were looking for especially large grizzlies, but were not able to find any. Therefore we decide to search for them at the Pacific coast of Alaska, where the climate is moderate: on the Kodiak Islands. The Kodiak Island Group offers unusually good conditions to bears. There one also sees bear mothers with 3-4 cubs. In the cold regions of Alaska they only have up 2 cubs at the most.

The good conditions on the islands allow the Kodiak grizzlies to grow into a subspecies of the brown bear, which is especially large and heavy. That made them famous. Sport hunters shoot there the large bears. Since there is however much fodder, many cubs are born, which replace the losses. Therefore we do not find any really large bears there. Each animal needs there a home range of 200 km². Trophy hunters have shot there most of the large bears, completely legally.

Therefore we sailed with our boat to the Aleutian Islands in the west of Alaska. The sea is very stormy: in the north the Bering Sea. And south of us there is the Pacific. At the Aleutian Islands the difference between low tide and high tide is about 7 meters.

Coastal brown bears graze at the beach on the sea-grass meadow. Two females graze off there the salt-grass without stopping. It contains important proteins and mineral salts. These giants will only find there enough to eat, if they eat all the time.

A female with cubs needs up to 20.000 kilocalories per day, to raise her cubs and to put on enough fat supplies for the winter. If she only ate this sea-grass, she probably would not be able to take in enough food.

On the Aleutian Islands there are no mice and lemmings. And bird nests are there rare at the coast. During the last decades, no human beings have been on these islands and bays. The brown bears swim there from island to island, to plunder the nests of the birds.

At low tide large mud flats appear at the beach. And on this mud we see the tracks of bears. The bear has dug deep holes into the mud, and very many shells of shell-fishes lie around on the ground.

Then we meet on the shore of this bay an enormous coastal brown bear. It is 20 years old. It is a male. He weighs more than 15 hundredweights (750 kg). He eats there hard-shelled Jacob’s shell-fishes. Here one has never hunted them systematically. During centuries, such giants can grow up undisturbed. In other places salmon or fat meadows attract the bears. Here the shell-fish banks do attract them. At low-tide everywhere bears are on the mud flat searching for shell-fishes. 

On these islands the large salmon migrations take place only in the late summer. Pure carnivores, which only live on the flesh other animals, will starve here. And the herbivores, which only live on plants, will not be able to eat the shell-fishes and the fishes.

The Jacob’s shell-fishes in the mud, on which they live now, are so evenly distributed, that there is hardly any envy for fodder. The mud bottom contains enormous amounts of them. For weeks these brown bears live only on the Jacob’s shell-fishes.

Then the large brown bears move from the bay over the mountain range into the hinterland, to the fat grass meadows. The mating time begins. There we meet also a she-bear with 4 cubs. Here the climate is very moderate, like on Kodiak.

Now in late summer the time of abundance begins for the coastal brown bears. Now in late summer the really large salmon swarms do arrive. But here something is different. The salmon hardly leave the seawater. They do spawn already in the tidal area of the fjords. Here are hardly any rivers, into which the salmon must swim up, nor are there any rapids, which the salmon must overcome. This small bay is for the salmon already their final goal, their end-station.

The bear catches the salmon and has taken in again 4000 calories for his reserve of winter bacon.

The mothers are able to feed their cubs now with fat fish and milk so well, that they will gain several kilos per week.

For the pregnant she-bear it is now, before the winter begins, especially important, that she is well nourished. Because only in the female, which has stored enough fat in her body, the embryos will develop any further. If the pregnant she-bear is badly nourished, the embryos will die. She will not be able to have then any cubs.

On the mainland of Alaska: A brown bear digs itself a sleeping-cave. Their winter-dens lie far up on the north-facing slope of the mountains. In the cold cave they are protected against early thawing and melt-water.

During the winter the bears sleep, because they do not find then anything to eat for months. If they would wake up in warm weather too early, they would have to hunger for a long time. Because then their metabolisms has adjusted itself again to its normal condition. In northern latitudes the grizzlies do spend up to 60% of the year in a deep sleep in such caves. That seems to be also the reason, why the bears in the north of Alaska are much smaller than those at the Pacific coast in the south.

On Kodiak and the Aleutian the climate is much more moderate, than on the mainland; because the sea, which surrounds them [and the warm Japanese Gulf Stream] are much warmer. One assumes that many of the bears on the Aleutian Islands do not hold a real winter sleep at all. Because they find there enough fodder also in winter, so that they can remain active. They grow up then to those legendary giants." After: Andreas Kieling, Grizzly Giants (2003)

Note: The large coastal female brown bear with cubs in autumn must take in each day 20,000 calories, by eating the fat salmon, which she catches. Because only, if the pregnant she-bear has stored enough fat, the embryos will be able to grow up. If she is too lean, too poorly nourished, when she goes into her winter sleep, the embryos within her will die. A fat salmon contains there about 4000 calories. Therefore she must catch and eat each day at least 5 salmon. Only by eating grass, she will not be able to put on enough fat. Because the bear does not digest the grass as well as a hoofed animal." - 10 November 2003, 18:59 o’clock ARTE, Grizzly Giants, by Andreas Kieling.

The Brown Bear / Grizzly in Alaska, by Sterling Eide, Alaska Department of Fish and Game, Wildlife Notebook Series.

“In popular usage brown bear refers to members of the species found in coastal areas, while those found inland are commonly called grizzlies. In this paper ‘brown bear’ is used in the general sense; it refers to all members of Ursus arctos.

Bear weights vary throughout the year. Bears weigh less in the spring and early summer. They gain weight rapidly during late summer and fall and are waddling fat just prior to denning. At this time most mature males weigh between 500 and 900 pounds with extremely large individuals weighing as much as 1,400 pounds. Females weigh one half to three quarters as much.

The hairless young, weighing less than a pound, are born the following January and February in a winter den. Litter size ranges from one to four cubs, but two is most common. The cubs remain with their mothers through their second year. Brown bears give birth to a new letter every two or three years.

The brown bear is omnivorous. Common foods include berries, grass, sedge, horsetail, cow parsnip, fish and roots of many plants. Flesh of game or domestic animals is eaten when it is available. The brown bear is probably not a significant predator on big game species except possibly during spring when the young are most vulnerable. Bears are fond of carrion and will feed on carcases of any animals they find.

Bears usually enter dormancy in November and December and emerge during April or May. Dormancy is longer in areas having severe climates. Females with new-born cubs emerge later than single bears. The den is often a natural shelter between tree roots or rocks or may be an excavation dug by the bear. Dens are most common at high elevations near timberline, but may be found anywhere from sea level to alpine areas.” – Sterling Eide.

Brown bears near the coast of southern Alaska, at a river, where the salmon come up from the Pacific Ocean, to spawn. Here the large coastal brown bears are catching salmon at the rapids. From: Bernard Stonehouse, Animals of the Arctic the ecology of the Far North (1971:124)

Denning characteristics of brown bears on Kodiak Island, Alaska.

By: Lawrence J. Van Daele, Alaska Department of Fish and Game, Anchorage, Alaska, and co-workers. In Int. Conf. Bear Res. Manage. 8:257-267 (1990)

Study Area

“The Kodiak archipelago is located in the Gulf of Alaska, approximately 400 km southwest of Anchorage, Alaska (Fig. 1). Kodiak Island is the largest island in the archipelago, encompassing 9,600 km². The region has a maritime climate characterized by cloudy skies, cool temperatures, moderate to heavy precipitation, and frequent windstorms. Maximum temperatures generally range from 13-18°C and winter temperatures below -6°C are infrequent. Annual precipitation at Kodiak city averages 157 cm, and occurs primarily as rain near sea level and snow in the higher elevations from October to May. In general, the southwest portion of the island has warmer summers, cooler winters and less precipitation than the northern part.

The Terror Lake study area includes 774 km² on the northern portion of Kodiak Island. Inland topography varies from rolling hills and gentle valleys to steeply ascending ridges and peaks to elevations of 1,340 m along tributaries into Kizhuyak and Terror Bays. Vegetation varies from marine aquatics in the bays to hillsides covered with dense shrub thickets, interspersed with meadows. Alpine vegetation includes low willow (Salix spp.), sedges (Carex spp.), and ericaceous heath. Salmon are abundant throughout the summer with pink (Oncorhynchus gorbuscha), chum (O. keta), and coho salmon (O. kisutch) being most common.

The Southwest Kodiak study area encompasses 1,231 km² between Uyak, Deadman and Olga Bays. The topography is typified by wide flat valleys, rolling foothills, and occasional areas of steep terrain. The highest peak (997 m) and the most rugged terrain occur in the southeast portion of the study area. Lowlands support a mosaic of willow and herbaceous cover, with drier sites dominated by heath vegetation. Vegetation on mid-elevation slopes is similar to that in the Terror Lake area, but shrub thickets are not as extensive. Alpine vegetation is similar to that found in the Terror Lake area, but is less extensive.  Salmon are abundant from June through October, and occur in greater numbers and over a larger percentage of this study area than in the Terror Lake area. Sockeye (O. nerka), (O. tshawytscha), coho, pink, and chum salmon all occur in this area.

Brown bear densities were similar in both areas (1 bear/2,9 km² at Terror Lake and 1 bear/3.5 km² in Southwest Kodiak, but home range sizes were considerably different. At Terror Lake, the average annual home range size for radio-collared female and male bears was 28 km² and 133 km², respectively. In Southwest Kodiak, the average annual home range size for radio-collared female and male bears was 92 km² and 219 km², respectively.” Lawrence J. Van Daele (1990:257, 258)

Some male bears do not hibernate

“The failure of some males to den did not appear to be affected by inter-annual variations in food availability or weather conditions. Some males were active throughout the winter during every year of the study. More than 25% of the radio-collared males at Terror Lake did not den during at least 1 of the winters of the study. It is not uncommon to see bear tracks throughout the winter months on the Kodiak archipelago. We found no published reports of non-denning brown/grizzly bears, but non-denning black bears have been reported in Virginia and North Carolina (Hellgren and Vaughan 1987). The relatively warm winter climate and long seasonal availability of food probably allow some bears to remain active for longer periods of time on Kodiak compared to other portions of brown/grizzly bear range.

Non-denning bears apparently spent much of the time bedded in shrub or spruce microhabitats and intermittently travelled relatively short distances within their normal home ranges. Although these bears never entered dens, their behaviour appeared to be similar to ‘walking hibernation’ described by Nelson et al. (1983) for bears that had recently emerged from hibernation. No data on winter feeding were collected during this study, but it is suspected that non-denning bears reduced their food intake and may have experienced lowered metabolism periodically.”

By: Lawrence J. Van Daele, Alaska Department of Fish and Game, Anchorage, Alaska, and co-workers. In Int. Conf. Bear Res. Manage. 8:265-266 (1990)

Terror Lake and Southwest Kodiak brown bear study areas, Kodiak Island, Alaska. From: Lawrence J. Van Daele. In Int. Conf. Bear Res. Manage. 8:58 (1990)

Woolly mammoth in the Yukon Territory. After: John Storer, Discover Beringia.