Bears are preparing for winter

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Most bears in the Berenbos ('bear forest') in Ouwehands Zoo (The Netherlands) go into hibernation in November. The bears have built up a fat layer during the summer which should get them through the winter months. This is clear from their round shape and their beautiful, thick fur.
In nature, bears have a very varied diet, not only with respect to the kinds of food they eat, but also with respect to the quantities of food they consume. The summer is a period that is very rich in food. The bears eat a lot then and build up a subcutaneous fat layer. This is a reserve for the winter period when food is scarce. In 1998 the Berenbos introduced the Natuurlijk Voedsel Programma (NVP) (‘natural food programme’), imitating the natural conditions for wild bears as much as possible. Since its introduction the bears in the Berenbos actually sleep during the winter and they stay in hibernation much longer.

Hibernation is a way to get through a period of food scarcity. The bear’s body temperature and heart rate are lowered and the animal relies on its fat reserve. The bears eat very little to nothing at all. In the spring the body temperature and heart rate go up again and the animals wake up. They may have lost up to 45% of their body weight by then. First the bears are bit droopy and stiff. They start eating only grass, but soon they eat everything that is offered to them.
In the NVP programme the bears are fed at varying times and locations, and the food is hidden. The menu varies from month to month. Hardly any food is offered during the winter. In the spring the bears get tubers, fish, meat, fruits and honey. In the middle of summer the bears eat many fruits and in the fall they mainly eat nuts.