Gemma Wyer answered A baby bear is called a cub. Brown Bear A brown bear cub weighs just one and a half pounds at birth, but a fully grown, male brown bear can weigh up to twelve-hundred pounds. Cubs can climb trees to escape danger but, once they become adults, they are too heavy to climb. Black Bear A black bear cub weighs less than one pound, but twin cubs are common. An adult black bear can grow to up to six-hundred pounds. A cub will stay with its mother for a year and a half before venturing off on its own. Grizzly Bear Commonly, grizzly bear cubs are born as twins, and the mother will stay with her offspring for two years. The standing height of a grizzly bear is seven feet. Polar Bear Polar bear cubs will nurse for up to eighteen weeks, and the cubs will first venture out of the den at three or four months old. Cubs stay close to their mothers for the first few months and learn all the necessary survival skills from her.