This is the VOA Special English SCIENCE REPORT.
An American scientist has found that many images of dinosaurs may be wrong. For years, pictures of the ancient creatures have shown their nose openings near the top of the head. The new study suggests the dinosaurs’ nostrils were just above the mouth.
Dinosaurs used their nostrils to breathe, smell and control their body temperature. The new theory could help explain how the huge creatures were able to survive by using their sense of smell to find food, a mate and possible enemies.
Lawrence Witmer of Ohio University in Athens, Ohio led the study. The publication Science reported his findings.
Many of the early dinosaur remains recovered by scientists were from huge creatures called sauropods. Scientists believed that sauropods must have lived in water because their bodies were so huge and their necks were so long.
Nostrils high on the head would have permitted the dinosaurs to breathe while partly under water. The discovery of a sauropod head bone in Eighteen-Eighty-Four added support for this belief. The skull had a large hole at the top of the head.
Professor Witmer says experts learned years later that sauropods generally were not sea creatures. But he says the earlier theory about nostril position was extended to other dinosaurs.
Only dinosaur bones have survived as fossil remains. Scientists have never recovered dinosaur remains of soft tissue. Scientists interested in the physical appearance of dinosaurs often study birds and animals similar to the ancient creatures. Professor Witmer examined forty-five kinds of birds, crocodiles and lizards that are the closest living relatives to dinosaurs. He noted the placement of soft tissue through hundreds of x-ray images and by cutting pieces of tissue.
Soft tissue leaves markings on bone. Professor Witmer used this information to make a map of the likely position of soft tissue in the dinosaurs’ noses. He found that the birds and reptiles he studied share a common nostril position.
Professor Witmer found that the hole scientists once thought was a nostril in dinosaurs is just one part of the larger nasal passage. He found that the nostrils were farther forward and closer to the mouth. He says this new nostril position was true for all dinosaurs.
This VOA Special English SCIENCE REPORT was written by George Grow.