Bear Cubs Emerge From the Den | National Geographic

NARRATOR: But imagine seeing the park with fresh eyes, and every view a rare glimpse into a hidden world just like this one. A black bear and her cubs, a typical litter of three. For five months, she hasn't stirred. Even as their mother slumbered, the cubs nursed on a rich diet of super-fatty milk. Over the winter, her own weight dropped up to 1/3. How she survived still stumps us.

During hibernation, her heart rate fell to just eight beats per minute, and somehow, she turned much of her bodily waste into protein. In the coming months, she must fatten up on what the forest provides. The survival of the fragile cubs depends on their mother. Her survival depends on the Smokies.

After weeks confined to a cubbyhole, new life makes its debut in the park. Black bears are born climbers with strong claws. Even a bear cub negotiates the trunk like a power lineman. Their debut draws attention. Our mom must stay alert. Coyotes will prey on the cubs. So will bobcats.

At night, the treetops offer refuge from predators that can't climb. In daylight on the ground, the cubs are vulnerable, so mom won't let them wander. For the next 18 months, they'll shadow their mother, their instructor and protector within a park that safeguards them from another enemy, man. Male cubs will grow up to be loners like their long-gone father. Females will rear their own offspring.

For now, three wide-eyed toddlers enter a world made for them, if they learn to make the most of it.