The largest living species on Earth is the blue whale (*Balaenoptera musculus*). Adult blue whales can reach lengths of up to 100 feet (30 meters) and can weigh as much as 200 tons or more. These magnificent marine mammals are filter feeders, primarily consuming small shrimp-like animals called krill. Blue whales are known for their enormous size, slender bodies, and distinctive blue-gray mottled skin. They inhabit oceans worldwide and are known for their long migrations. Despite being the largest animals ever to exist, they face threats from ship strikes, entanglement, and climate change, leading to conservation efforts to protect their populations.