The Secrets of Sue the TRex

Interesting and/or little-known facts about Sue, the world's largest and most complete Tyrannosaurus rex skeleton ever discovered. She has been on display since 2000 in Chicago's Field Museum, since 1893 the city's showcase and storehouse of mummies and other anthropological souvenirs, plus fossils and preserved plants and animals. The museum, with support from academic, business and philanthropic institutions, purchased the bones at auction in 1997.

Sue might be a boy. She was named for its discoverer, paleontologist Sue Hendrickson, who found Sue in 1990 while walking her dog on ranchland near Faith, SD. Scientists remain uncertain regarding the dinosaur’s gender, but research continues. "We're getting closer and closer," says Marie Orendach, who has led Sue tours at the museum since the unveiling.

Sue cost the museum $8.36 million. Just for the bones. It was an auction. The winner was Maurice Williams, after a long court fight over who actually owned the ranchland -- which is part of the Cheyenne River Indian Reservation -- and the bones on it. The court ruled in favor of Mr. Williams, and Mr. Williams cashed in.

Sue helped the museum draw 2.4 million in 2000, her first year there. Having the Dead Sea Scrolls on display the same year didn't hurt. The museum drew 1.2 million in 2010, about average for a year without a new blockbuster exhibit.

The head on Sue isn't Sue's head. The real one is up on a balcony overlooking the rest of her, in a display case. Reason: The original weighs 600 pounds and couldn't be supported by the skeletal neck.

Sue's actual head weighs 600 pounds? That's the fossilized/mineralized weight. When it was mere bone, it was lighter. It weighed a ton when they found it. Of course, then it was filled with rock.

Then the head on the otherwise genuine Sue is . . . Yep. It's plastic.

Sue, in her prime, weighed 7 tons. Including the unfossilized head.

Sue sometimes disappoints people. "I see it in your eyes," Orendach tells folks on tours. "You thought it would be bigger."

Sue is about as tall as a 1-story house. As she stands, kind of hunched over in her natural posture, she's listed at about 13 feet tall. And she's about 45 feet long, depending on how she's measured. It's not her fault she looks puny on display next to huge stuffed elephants in huge Stanley Field Hall.

Sue isn't the biggest dinosaur in the Field Museum. That honor belongs to a 72-foot-long unnamed Apatosaurus that's upstairs and around the corner from Sue's real head. The Apatosaurus is commonly, but wrongly, referred to as a "Brontosaurus.”

Sue isn't the pale-boned skeleton visitors expect. The bones are a deep brown, the color of minerals -- mainly iron -- in which she was buried for 67 million years. "Most people don't think they're real, because of the color," says Orendach. "It's the actual color."

Are all Sue's bones real? It is estimated that 90% to 95% of the bones are real, if you reattach the head. Exceptions are a few vertebrae, bits of ribcage and arm, and her left foot. The dinosaur was found largely intact.

How long did it take to carefully dig Sue out of the mountain? Seventeen days, by 4 commercial paleontologists.

Some of Sue's vertebrae are scuffed-looking. Sloppy commercial paleontologists? Nope, it’s arthritis. Sue likely lived about 28 years; maximum age for the creatures is estimated at about 35, so she was getting up there.

Those holes in Sue's jaw were there when she walked the Earth. Likely the work of parasites, says Orendach, and they might have been what killed her.

Sue was constantly losing and regrowing teeth. The teeth were as large as 12 inches; the replacement process took 2 to 3 years. Some of the teeth were serrated, like a bread knife.

Sue is related to birds. No one knows for sure which evolved from which.

Sue isn't the only tyrannosaurid in the Field Museum. Upstairs next to the Apatosaurus/Brontosaurus is a close cousin, a Daspletosaurus, which used to be the museum's star dinosaur until Sue came along. Not only was this (also nameless) skeleton shipped upstairs, but its once fearsomely erect stance was reduced to a humble bow after scientists determined this species never did roaring-grizzly imitations.