An icon of the rugged landscape of the western United States, the bighorn sheep is one of the most majestic members of the desert ecosystem. It is also one that has adapted in amazing ways. Bighorn sheep can go for weeks without visiting a permanent water source, getting the water they need from food and rainwater found in small rock puddles. They also use their horns to split open barrel cactus and eat the watery flesh. When green grasses are available, they don’t need to drink at all, however during summers they need to drink water every few days. They can tolerate losing up to 20 percent of their body weight in water loss, and bounce back quickly from dehydration. By being able to survive for long periods away from a steady source of water, they can better avoid predators. They can also survive slight body temperature fluctuations, unlike many other mammals which need to maintain a steady temperature.