[Science Report]:Dinosaur Noses


This is the VOA SpecialEnglish SCIENCE REPORT.

An American scientist has found that many images of dinosaurs maybe wrong. For years, pictures of the ancient creatures have showntheir nose openings near the top of the head. The new study suggeststhe dinosaurs' nostrils were just above the mouth.

Dinosaurs used their nostrils to breathe, smell and control theirbody temperature. The new theory could help explain how the hugecreatures were able to survive by using their sense of smell to findfood, 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 werefrom huge creatures called sauropods. Scientists believed thatsauropods must have lived in water because their bodies were so hugeand their necks were so long.

Nostrils high on the head would have permitted the dinosaurs tobreathe while partly under water. The discovery of a sauropod headbone in Eighteen-Eighty-Four added support for this belief. Theskull had a large hole at the top of the head.

Professor Witmer says experts learned years later that sauropodsgenerally were not sea creatures. But he says the earlier theoryabout nostril position was extended to other dinosaurs.

Only dinosaur bones have survived as fossil remains. Scientistshave never recovered dinosaur remains of soft tissue. Scientistsinterested in the physical appearance of dinosaurs often study birdsand animals similar to the ancient creatures. Professor Witmerexamined forty-five kinds of birds, crocodiles and lizards that arethe closest living relatives to dinosaurs. He noted the placement ofsoft tissue through hundreds of x-ray images and by cutting piecesof tissue.

Soft tissue leaves markings on bone. Professor Witmer used thisinformation to make a map of the likely position of soft tissue inthe dinosaurs' noses. He found that the birds and reptiles hestudied share a common nostril position.

Professor Witmer found that the hole scientists once thought wasa nostril in dinosaurs is just one part of the larger nasal passage.He found that the nostrils were farther forward and closer to themouth. He says this new nostril position was true for all dinosaurs.

This VOA Special English SCIENCE REPORT was written by GeorgeGrow.

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