It's October in Zambia's Luangwa Valley. the hottest and harshest time of year. But this year dry season conditions are exacerbated by a global El Niño event; the Valley is in the throes of drought. There's been no rain since April and desperate animals are drawn to the only remaining source of water in the Valley, the dwindling Luangwa River. The last remaining deep pools are inhabited by hippos - hundreds squashed together in the only water deep enough to submerge them. As tempers flare and skirmishes break out, it's a dangerous place for baby hippos, dwarfed by the three-tonne adults.