It is a species of baleen whale (whales with bristles in their mouths that are used to filter food from water). The blue whale weighs approximately 150 tons (135 metric tons) and may reach a length of more than 98 feet (30 meters). The largest accurately measured blue whale was a 97-foot female that weighed nearly 200 tons. There are reports, however, of 108-foot catches that may have reached 220 tons.