Crustaceans are a diverse group of aquatic animals that include familiar creatures like crabs, lobsters, and shrimp. They have hard outer shells, called exoskeletons, which protect their bodies. Crustaceans typically have multiple legs and antennae, helping them navigate their underwater environments. They can be found in oceans, rivers, and even on land. These animals play a vital role in the ecosystem as both predators and prey. Many species are also important for human consumption, making them a significant part of the seafood industry. Crustaceans contribute to the food web, supporting various marine life and helping maintain the balance in their habitats.