Everyone is hoping for rain. In Britain, rainfall represents disappointment and occasionally some flooding. In large parts of Africa, it means the difference between life and death. For both man and animal, the rainy season is integral to life, it brings food and water for the millions who live in these otherwise arid places.

Dusty, dry and thirsty, I spent last week in one of Tanzania’s national parks. Across the vast plains, a seemingly endless procession of animals stretched to the horizon and beyond. The thousands and thousands of hooves created mighty clouds of dust. The rising sun painted the whole landscape a golden hue. From a balloon high above the Serengeti I could see the scale of one of the most vibrant, complex ecosystems on the planet.

The huge herd of animals were wildebeest, also known as gnu. The hyenas have evolved here to follow this great migration while remaining in their dens. They have become commuter hyenas. Lions also feast off this mighty herd, giving way to nomadic male lions, which also follow this extraordinary movement that crosses from Tanzania into Kenya.

Without the rain, the lakes, ponds and rivers had largely dried up. Below me, hundreds of hippos were crowded into tiny pockets of standing water. If the rains don’t come soon, these great pods will certainly die.

Over the course of the week, huge clouds began to build on the horizon, teasing us with the promise of rain. If only they could have a little of ours. In Great Britain we have become complacent with our ready supply of water.

Here the search has become a daily battle. On the boundary of the park, the Maasai people have begun sacrificial rituals, offering goats to the rain gods. Without rain their valuable cattle will starve, and so will they. The animals of the Serengeti are already on the move, in search of better grazing and the hope of moisture. For me this was just the beginning of my journey. Over the next year I will be following the wildebeest as around 1.3million migrate west and then north to the rich habitat of the Maasai Mara in Kenya. Before they get there, they’ll have to contend with the hungry crocs of the Mara river. Think about that the next time you turn on your tap for a glass of water.