The blue whale holds the title for the biggest animal on Earth. These colossal marine mammals can reach lengths of up to 100 feet and can weigh as much as 200 tons or more. Blue whales are filter feeders that primarily consume tiny shrimp-like animals called krill. Despite their vast size, they are gentle creatures that migrate across oceans in search of food and breeding grounds. Their population was severely depleted due to whaling in the 20th century, but conservation efforts have been implemented to protect them. The blue whale's impressive dimensions and graceful nature contribute to its status as a wonder of the natural world.