Young animals face new challenges as winter envelopes the Rocky Mountains, and spring means the end of childhood. A grizzly mom prepares her cubs for hibernation, a mountain lion raises her kittens and a bison calf must learn to survive the snow. 

Wildlife cameraman Gordon Buchanan fronts the team helping scientists investigate the lives of some of Australia’s most iconic animals. Koalas, fruit bats and kangaroos take the cameras into their secret worlds.