Today I got back from Kenya where I have been following the world's largest animal migration as it crosses the Masai Mara. Each year more than 1.4 million wildebeest and 200,000 zebra and gazelle, relentlessly tracked by Africa’s great predators, migrate in a clockwise fashion over 1,800 miles in search of rain-ripened grass. 
This year the drought was so bad that I even spotted giraffe negotiating the Mara river. Giraffe very rarely brave rivers, their legs are so gangly they could easily slip and never recover. It took this lot almost half an hour to cross this shallow section of the river. It was tense watching them as they stepped gingerly across, carefully feeling with each foot before taking a step.
