Female bears are ready to mate between the ages of 3 and 8 years, but that will depend on their health and their weight. A female bear that is underweight cannot give birth. Bears, who usually prefer to live alone, get together in spring to find a mate.
Finding a mate can be quite tricky for the male bear. Throughout the year, the male bear can be a bit of a bully. Since they are larger than females, they have been known to kill females for food. Of course the female might be nervous and untrusting of the large male bear! The male follows the female at a distance for quite awhile until she feels safe and allows him to get closer. Once they’ve mated the male leaves and may never see her, or the cubs, again.
Three to nine months later, depending on the species of bear, cubs are born. For bears that live in colder climates, the cubs are born during hibernation. The mother bear nurses her babies and keeps them warm as they grow and mature. Pandas, Asiatic and Brown bears have a cool internal thing called “delayed implantation” which allows the female to hold off fertilization of the egg until a later date and time the birth of her cubs to happen during hibernation where they will be born in a safe and warm place.
Bear cubs are born helpless. They can’t see or hear and they have no teeth. They are small…like a kitten, weighing around 454 g (1 pound) or less. Mothers will carry their babies by their heads, except for the Sloth bear. She will carry them piggyback for the first few months while she travels or hunts.
Bears that live in warm or tropical climates and do not need to hibernate can mate at any time.