The largest animal that has ever lived is the blue whale. These magnificent creatures can grow up to 100 feet (30 meters) long and weigh as much as 200 tons or more. Blue whales are truly colossal, with a heart weighing approximately as much as a small car. They are filter feeders, primarily consuming tiny shrimp-like animals called krill, and can eat several tons of them daily during feeding periods. Despite their immense size, blue whales are gentle giants, known for their grace in the water. Unfortunately, they were heavily hunted in the 20th century, leading to significant population declines.