Bear mating season begins in May and June. During this time, the animals give up their solitary existence. Once a male has found a suitable partner, he needs to be careful because he has to gain her trust first. He sometimes has to take a swipe if the female doesn’t accept his advances. If she does, both roam the territory together for a while until mating takes place. After that, they part ways and both keep an eye out for potential new partners. This increases the chance that fertilization will actually occur.
Fertilized egg cells do not nest in the uterus until autumn (before that we speak of germ dormancy) and only continue to develop when the bear has already eaten enough weight for the wintan. For this reason, most young animals are born at the same time – around February, in the winter den. In very lean years, the egg cells can die off, because the survival of the young would be unlikely.