The highest and the lowest places of our planet also offer niches where life thrives. High up in the Alps, animals have developed particular strategies to survive. Short, hot summers follow long, hard winters - seasonal extremes that test the endurance of Alpine inhabitants. Sri Lanka's cloud forests are home to an army of specialists. At 1,500 metres above sea level the forests are high enough to bring winter frosts. While life in higher altitudes often is accompanied by coldness and a lack of oxygen, animals and plants that prefer the sweet life at sea level must ...

Orangutans forage early in the day inside the rainforests of Sumatra - before the heat becomes unbearable. When the sun reaches its zenith all activity stops and the primates retreat to their shady nests below the canopy to wait out the heat. Winter in northern Yukon Territory - a frozen white landscape stretches into the distance. But high up on the Arctic Circle, one unique river still flows - because it's fed by an underground spring. Chum salmon exploit this anomaly. They travel thousands of kilometres to spawn here - later than anywhere else. And grizzlies ...

In the Amazon forest, the largest rainforest on Earth, animals must deal with high rainfall and periodic flooding. They have to find clever ways to survive. When ponds in Sri Lanka dry out at the height of summer they expose the last remaining fish to hungry crocodiles and storks. But when the banquet is over, predators must find food elsewhere ¬. In the desert of Namibia, rivers are mostly desiccated beds of sand. But sand grouse, Oryx and giraffes find the last remaining pools of water. Drought can also be live-giving: along the sand banks of the fast evaporating ...