Steller's sea cow was a large marine mammal that lived in the cold waters of the North Pacific, particularly around the Bering Sea. It was discovered in 1741 by the naturalist Georg Wilhelm Steller and could grow up to 30 feet long. This herbivorous creature primarily fed on kelp and other aquatic plants. Unfortunately, Steller's sea cow became extinct by the late 18th century, just 27 years after its discovery. Overhunting by humans, along with habitat loss, contributed to its rapid decline. Today, it serves as a reminder of the impact of human activities on vulnerable species.