Brown bear

Chapter 02

Behaviour

Activity peaks in the morning and early evening. Bears can be about at any hour, but those living where they are likely to meet people are more often fully nocturnal; where interaction is rare, most adults are crepuscular while yearlings and newly independent bears are active throughout the day. From summer through autumn a brown bear can double its spring weight, laying on up to 180 kg of fat to carry it through a lethargic winter. They are not true hibernators and wake easily, but both sexes prefer to den somewhere sheltered — a cave, a crevice, cavernous tree roots, a hollow log. Mating runs from mid-May to early July, later the further north. Females mature between four and eight years, males about a year later, when they are big enough to compete. A female comes into oestrus every three to four years and may mate with up to four males, occasionally eight. Despite the reputation, the brown bear is not markedly carnivorous: it draws up to 90 per cent of its dietary energy from plants. It eats berries, grasses, flowers, acorns, pine cones and fungi, and among bears it is uniquely equipped to dig for roots, bulbs and shoots, using long claws to open the ground and powerful jaws to bite through. In spring the mainstays are winter-killed carrion, grasses, shoots, sedges, moss and forbs; fruit matters increasingly through summer and early autumn; and roots and bulbs become critical in autumn for inland populations when the fruit crop is poor.