Blue whales were larger, but not by much. Modern blue whales (Balaenoptera musculus) can grow to lengths of more than 30 meters (98 feet) and weight up to 180 metric tons (200 tons). In contrast, the longest titanosaur, Dreadnoughtus, measured 26 metres (about 85 feet) long, and the heaviest titanosaurs, Patagotitan and Argentinosaurus had estimated weights of 63.5 metric tons (70 tons) and 70 metric tons (77 tons), respectively.