MUSEUM CAMPUS — Scientists at the Field Museum are removing an arm Thursday from Sue the T. rex — the most complete Tyrannosaurus rex in the world — to answer a simple question: Why does such a giant creature have such little arms?
“One of the big mysteries about T. rex is its tiny forelimbs,” said Pete Makovicky, associate curator of dinosaurs at the Field Museum. “We don’t know how it used them. But there could be clues in the fossils."
The scientists will send Sue's right arm to the Argonne National Laboratory in suburban Lemont, which will use special "micro-CT scans" to look for clues.
“These X-rays will give us a map of the blood vessels and muscle attachments in the bone, which have never been seen before,” said Carmen Soriano, paleontologist and beamline scientist at Argonne. “We’ll be able to get incredible details about the structure of Sue’s bones and how she used her arms, without damaging the fossil itself.”
Named after the scientist who discovered it, Sue Hendrickson, the dinosaur stands 13 feet tall, is 42 feet long, and has 58 very sharp teeth. It's skull alone weighs more than 600 pounds — and is displayed separately because of its weight. (The lighter replica sits atop the skeleton).
The museum will host an "arm removal gala" at 10 a.m. Thursday. Argonne will return Sue's arm a few days afterward.
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