Tardigrades, also known as water bears, are tiny, water-dwelling animals that measure about 0.5 millimeters in length. They are known for their resilience and can survive extreme conditions, including high radiation, extreme temperatures, and even the vacuum of space. Tardigrades have a unique ability to enter a state called cryptobiosis, allowing them to endure harsh environments by essentially shutting down their metabolism. These microscopic creatures are found in various habitats, from deep oceans to the highest mountains, and even in moss and lichens. Tardigrades feed on plant cells, algae, and small invertebrates, using their specialized mouthparts to suck out nutrients. Their fascinating biology makes them a subject of scientific research, particularly in studies related to extremophiles and astrobiology.