Mammals dominate the planet thanks to their warm blood and the exceptional care they provide for their young. Weeks of filming in the bitter Antarctic winter reveal how a mother Weddell seal wears her teeth down keeping open a hole in the ice so she can catch fish for her pup. A powered hot air balloon produces stunning images of millions of migrating bats as they converge on fruiting trees in Zambia. A gyroscopically stabilised camera moves alongside migrating caribou, and a diving team swim among the planet's biggest fight as male humpback whales battle for a female.

Originally released by BBC Worldwide Learning, 2009. Streaming video file encoded with permission for digital streaming by Infobase on November 21, 2019.