During winter, the bear goes into hibernation. He neither eats, nor drinks during that period and survives on the body’s high percentage of fat, built up in summer. During hibernation the bear can burn about 40% of his bodyweight. When the bear, in spring, starts moving around again food may still be scarce and the bear continues to lose weight until the early summer period when nature becomes more succulent and the reindeer and elks give birth to their calves.
From the point of view of energy provision, the bear takes in about 20% by eating ants and the larva and eggs of ants. Else, the bear is mainly an herbivore, eating different species of berries and juicy types of herbs. Blueberries are among the bears favourites. A couple of American researchers observed a brown bear in the process of consuming 184 000 blueberries in one day! Many a day berries constitute about half of the bears energy-intake. The bear also likes cranberries, lingonberries, rowanberries, as well as acorn, honey from bees, mushrooms, hazelnuts, the (sweet tasting) roots of oats and other plants. In former times, the bear was considered to do much damage to oat fields. The meat of different animals supplies about 25% of the bear’s energy consumption. It comes from elk or reindeer calves, preferably also from the carcasses of dead animals. Many a time the bear finds, during the elk-hunting period, the butchers rests, or he finds animal waste on a garbage dump or in garbage cans. Refuses are a rich source of energy for a bear; it will build up fat reserves for the wintertime.
Smaller bears are not very skilled in taking full grown elks or reindeer. During summertime, when there are many elk calves around in the forests, the bear can notably reduce the elk strain locally.
Part of the reindeer owners submit, that in the bear rich areas, some of the bears specialize in taking elk calves.
It is easy to recognize the bear by its strong legs, the coarse neck, the massive head and the hunchback. The size of the bear is much varying. The average weight is within 60 – 250 kg. Some species get much bigger than that though. The heaviest bear ever shot in Sweden showed a weight of 338 kg. The bear has a big head and a protruding nose part. The nose is the most important organ of perception, and the bear’s sense of smell is phenomenal. The sense of hearing is extremely good, that of sight though probably not up to the level of humans. When the bear gets unsure, he will often raise up on the hind legs, in order to better perceive what is in front of him. It is not a threat. The bear can run faster than any human. Even big bears are god tree climbers.
The bear has the walk of a plantigrade animal, with very big feet, 5 toes on every foot and substantial pads. Each toe has a strong claw which cannot be retracted. The bear moves either walking, or trotting. It can also move in gallop or move jumping. The normal way is trotting but the bear can run with an incredible speed over short distances. The impressive corner teeth disclose the bear as a predator; the blunt molars chew the vegetarian food.
The world’s biggest brown bears are located in Kodiak in the state of Alaska (USA) and on the Kamchatka peninsula in Siberia. These bears can weigh up to 500 – 600 kg. This impressive weight can probably be explained by the abundance of easily accessible salmon in the rivers.
When taking off the bear’s fur it resembles in a horrible way a human being. But even in its normal appearance there are some similarities. The bear takes a liking to standing on 2 legs, its eyes are directed forward and it can pick up even small fruits with its forefeet.
The phase of hibernation
The most fascinating property of a bear is, succeeding in being asleep during nearly half a year. Normally the bear goes into hibernation from the end of October till the turn of the month April/May. Hibernation is somewhat longer in the north, but slightly shorter in the south. It is the adaptation to be able to survive in winter, when there is little to no food.
Prior to going into hibernation the bear ceases to eat and drink and it looks as if it “empties its systems”. Thereupon the bear sleeps without eating, drinking, urinating or moving its bowels. All this requires several internal changes in the body and its organs. E.g. the body temperature decreases from 38 to 33 – 34oC; the number of heart beats go down from 40 to 10 beats per minute. This way, the bear spends less energy then when awake and it consumes less of its fat reserves built up in autumn.
Though the bear does not drink during approx. 6 month it does not suffer from a lack of water; the fat that the bear breaks down is reduced to water. When most of the fat reserves are consumed the bear gets thirsty and wakes up.
The bear, though sleeping the whole of the winter period, does not remain in total lethargy; it can wake up and return to sleep several times. Waking up happens oftener in the early time of hibernation. When a bear gets its sleep disrupted too often, it changes to another location for further hibernation.
The bear seems to choose the place of hibernation in advance and will visit the location several times during summertime. The location can be of different form and shape. It can be sort of a hole in the terrain, an old ant hill (much preferred), an overturned root part of a tree, in brushwood or in an opening between two blocks of granite. The location is often lined with peat or moss, fir twigs or grass. Big male bears often lie down under a big fir tree or on a bed of brush wood and let themselves get covered with snow.
Mating periods and cubs
The number of cubs varies from 1 – 4, more normal though 2 – 3. The cubs stay with the mother 1 – 2 years. The copulation takes place during the mating period in early summer, with a more intensive period between May 30th and June 10th approximately. The female then gives birth during January – February. The cubs are no bigger than guinea pigs. When they leave the site of hibernation they have grown to 2 – 4 kg. During the first and sometimes also the second year, they follow the mother closely. Cubs that happen to stray away from the mother do survive rather well already from the middle of their first summer alone. A female bear gets pregnant only once every two years, and often with longer intervals than that. Bears live a slow life; the females get sexually mature first when 4 years old and often considerably later than that. Bears can live a lengthy life of up to 30 – 40 years. The adult male usually lives a quiet single life. During some hectic late spring weeks, he tries to copulate with as many females as possible, chasing away their other suitors.
The bear takes long walks, particularly the males. They move in considerable larger areas than the females. A bear can easily go some dozens of miles a day. Adult bears live in home territories of much varying sizes. The females, that live in Sweden circulate on approx. 400 – 500 km2, an area as big as lake Hjälmaren . The home territories shrink when they have cubs with them. Males circulate on territories of 1 400 – 1 500 km2; this equalizes the whole area of lake Mälaren.
“Home territory” is an expression for an area where an animal leads its life; however, there may also come in further animals of the same species.
Many home territories do overlap each other. A territory can also be the area of one single animal that than defends its “home area” against intruders. This is not the case with the bears.