Each year, the seemingly delicate monarch butterflies undertake a multi-generational migration from Mexico all the way to Canada and back again.

Tracing ancient paths, wildebeests become a moving feast. But the biggest threat is the gauntlet, the saltwater crocodile filled Mara River crossing.

When you've got it all, why give it up? We expect animals to choose the easiest option for food and comfort, but that's not always predictable.