Africa - home to the greatest wildlife gatherings on Earth. But even in this land of plenty, wildlife faces huge challenges, from Africa's rich Serengeti to Africa's. For millennia, Africa's unique wildlife has managed to thrive, even in its most hostile corners, but today its greatest threat...

More than any other continent, North America is defined by extreme weather and seasonal change. For animals that live here this poses great challenges, but for those with a pioneering spirit it can also offer great rewards.