Reproduction and offspring

Mating season begins in May and June, and the bears temporarily give up their solitary way of life. If a male has found a suitable female as a partner, he must first prove himself and win her trust. Occasionally, the male has to put up with a blow from the female when his advances are unsuccessful. If the female does accept the advances, the pair will roam through the territory together for a while before mating. After mating, the bears separate and each searches for new partners, thereby increasing the chances of reproducing.

A fertilised egg then lies dormant and only implants itself in the womb in autumn. The egg will only develop if the female has gained enough weight for the hibernation period. This explains why bear cubs tend to be born at the same time, around February. The birth normally takes place in the hibernation cave. The egg may die off in times when there is not enough food, as a lack of food would endanger the survival of the young cub.

The offspring is born following a pregnancy of about seven months. A litter generally consists of between one and three cubs, weighing just 300-400 grams and measuring approximately thirty centimetres at birth. The milk of the mother is extremely fatty and helps the cubs to grow quickly. Within four months, the cubs weigh about four to five kilograms. The cubs are born naked, blind and without teeth and are utterly dependant on the mother. This dependency continues for three years, as the cubs learn everything they need to know to survive from their mother. They investigate their surroundings and accumulate their own experiences, but always return to the mother, who nurses them all the way through the upbringing. During this time, the mother is not able to reproduce again. This can occasionally cause male bears in heat to kill the young cubs, in order to conceive their own offspring.

Approximately half of the newborn cubs survive the first three years. Particularly male children are driven off at the end of the upbringing period, as a natural protection against incest. Female offspring are accepted within the territory a little longer.