Water bears, also known as tardigrades, are tiny, water-dwelling creatures that measure about 0.5 millimeters in length. They are known for their unique ability to survive extreme conditions, including extreme temperatures, radiation, and even the vacuum of space. Water bears have a segmented body and eight legs, which they use to move through their environment. These microscopic animals can be found in various habitats, including moss, lichens, and soil. They enter a state called cryptobiosis, allowing them to withstand harsh conditions by essentially shutting down their metabolism. When conditions improve, they can rehydrate and return to their active state.