The saguaro cactus of the Sonoran Desert can grow taller twelve meters and live for than 150 years. Its folded stem like an accordion to store water rain, and a large saguaro hold hundreds of liters. Instead of , it has sharp spines, reduce water loss and protect it animals. The cactus very slowly: at ten years old, it may be only a few tall.

Deserts receive less than about 250 millimeters of rain a year, yet they are home to a surprising variety of plants and animals. Each has found ways to obtain, store, or save water.

Many desert plants have shallow but wide-spreading roots that can quickly absorb water after brief rains. Others, like the mesquite tree, send roots deep underground to reach water far below the surface. Cacti carry out photosynthesis in a special way: they open the small pores on their surface mainly at night, when the air is cooler, which greatly reduces water loss.

Animals have their own strategies. The kangaroo rat of North America may never drink water at all. It obtains water from the seeds it eats and produces very concentrated urine. Many desert animals are active mainly at night, avoiding the hottest part of the day by staying in cool burrows.

These adaptations make desert life possible, but they also make it fragile. Because growth is slow, damaged desert ecosystems can take decades or even centuries to recover from disturbances such as off-road driving.