Though they have a crazy name, the Parasaurolophus had a very distinct look. They had a strangly shaped head with a long curved crest. Their crests were believed to help identify gender, increase hearing ability and even help regulate body temperature. Parasaurolophus were around 31 feet in life and weighed around 2.7 tons. They were found in North America around 75 million years ago, during the late Cretaceous Period.