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the brown bear: way of life & offspring

16.11.2017

A year in the life of a brown bear in the wild – from mating to winter sleep

Brown bears are loners and roam through fixed territories. In the wild, they can live to an age of around 25 to 30 years. Read here about a typical year in the life of a bear – its reproductive, feeding and resting cycle.

Mating time in spring and summer

The mating season for bears begins in May and June. During this period, the animals abandon their solitary way of life. Once a male has found a suitable female partner, he must proceed with caution –  first he must win her confidence. If the female does not accept his advances, he might get swiped by a paw. If she accepts him, the two roam together for a while, until they mate. Then they part ways and both look out for potential new partners. This way, the chance of fertilisation is bigger.  

Fertilised egg cells do not nest in the female's uterus until autumn (up to then they are dormant) and only develop once the bear has eaten enough to put on sufficient weight for the winter. This is the reason why most cubs are born at around the same time – approximately February – in the winter den. In lean years, the egg cells sometimes die because these young would probably not survive. 

communication:
Quiet & LOUD

Because bears are loners and do not live in a social group, the vocalizations they use to communicate are not very developed.

Young bears growl when drinking and squeal and snarl with playing. When the mother bear drives away her children after the rearing phase, she does so by snarling or 'barking'. 

Adult animals intimidate their rivals in a fight by fearsome roaring. 

Offspring: small at first, then rapid growth

Bear cubs are born after a gestation period of around 180-270 days. The newborn bears are naked, blind and toothless and are completely dependent on the mother. A litter usually consists of one to three cubs that weigh only 300 to 400 grammes at birth, and are around 30 centimetres long. The mother's milk, which is rich in fat, makes the cubs grow fast: after four months they already weigh four to five kilogrammes.  

In the next three years, they learn everything about a bear's life from their mother. They explore their surroundings with curiosity and make their own discoveries. But they always return to the mother who nurses them during the entire rearing phase. During this time, the mother animal is not ready for new young. This can sometimes cause a male intent on mating to kill her cubs in order to sire his own offspring. Only around half of the young survive the first three years. When rearing is over, the mother firmly drives away her offspring, especially the males. This serves to protect her from incest. Female young are allowed to remain in the territory for longer.