The largest type of mammal found in the ocean is the blue whale (*Balaenoptera musculus*). Blue whales are the largest animals to have ever existed, reaching lengths of up to 100 feet and weighing as much as 200 tons or more. These gentle giants primarily feed on tiny shrimp-like animals called krill, consuming up to 4 tons of krill each day during feeding seasons. They are known for their magnificent deep blue coloration and powerful calls, which can travel long distances underwater. Blue whales are currently classified as endangered due to historical whaling and habitat loss.