Lions

Follow the transformation of a helpless lion cub from a 4-pound toothless ball of fluff into a 400-pound accomplished killer, exposing its life-or-death learning curve in dramatic detail. Female lions do their best to teach their cubs how to hunt, but usually the little ones learn by trial and error. The lessons are hard and even deadly. Cubs are routinely bitten, bashed, kicked and crushed; more than half of all lion cubs die before their first birthday. (Source: National Geographic Wild)