A tyrannosaur's troubled past.

Tyrannosaurus rex may have been the largest carnivore ever to stalk the globe, but that doesn't mean the ferocious beast led an easy life. Paleontologists studying a T. rex specimen from South Dakota report that this individual suffered a number of major injuries and diseases throughout its life.

Discovered in August 1990, the specimen is the largest and most complete T. rex known, says Peter L. Larson of the Black Hills Institute of Geologic Research, Inc., a private company that collects and sells fossils. Several clues suggest that this animal, named Sue in honor of its finder, survived one or more attacks from other tyrannosaurs, Larson says. One rib harbors a tooth fragment within an abnormal overgrowth of bone, indicating the bone healed after a bite wound. A hole in the skull and a lump on the lower jaw could also represent healed wounds from a fight, Larson surmises.

Both the left and right fibulae show abnormal overgrowths--apparent indications that Sue recovered from two broken legs. ("We were thinking we might find the remains of a wheelchair next," Larson jokes.) The two fibulae probably fractured at separate times, because the animal could not have survived with two broken legs at once, Larson adds.

Another interesting pathology may reveal details about T. rex mating: Several of Sue's tail vertebrae are fused together, perhaps from an injury incurred furing copulation, Larson says. Although the animal's gender remains unclear, the shape of its bones suggests it was a female, he adds.

The Black Hills paleontologists think they have also discovered the eventual cause of Sue's death. The left side of the skull shows signs of an injury -- perhaps the bite of another tyrannosaur -- from which the animal apparently never recovered. Before that final battle, though, Sue apparently dined on Edmontosaurus. Larson and his colleagues found vertebrae from this herbivore buried with the T. rex specimen; the bones look etched, as if by stomach acid, he says.