The largest mammal in the world is the blue whale (Balaenoptera musculus). These magnificent marine creatures can reach lengths of up to 100 feet (30 meters) and can weigh as much as 200 tons or more. Blue whales are filter feeders, primarily consuming tiny shrimp-like animals called krill, and they can eat about 4 tons of krill a day during feeding season. Found in oceans worldwide, blue whales are known for their deep, resonant calls and impressive speed, despite their enormous size. They are currently classified as endangered due to past whaling practices, and conservation efforts continue to protect their populations.