Mammals\' ability to learn new tricks is the key to survival in the knife-edge world of hunters and hunted. In a TV first, a killer whale off the Falklands does something unique: it sneaks into a pool where elephant seal pups learn to swim and snatches them, saving itself the trouble of hunting in the open sea.

Mammals dominate the planet. They do it through having warm blood and by the care they lavish on their young.

How mammals developed from tiny forest dwellers to the dominant life form on the planet.