free debate

October 3, 2009

Who Killed Sue?

The mystery of how Sue died has been 67 millions years in the making. Sue is a Tyrannosaurus rex, and currently lives at the Field Museum in Chicago, Illinois, although it was initially discovered in South Dakota. It is the largest, most complete, and best preserved specimen ever discovered. Paleontologists have intricate detail on the fossil bones, including muscle scars and bone density. More interesting, however, are a series of small holes on the side of Sue's skull. Investigating these holes has helped paleontologists to learn about how this massive creature died.

One early guess about these holes is that another T. rex bit Sue here. It seems like a reasonable guess; the size and position of Tyrannosaur teeth about match up with the series of holes. Several scientists, including Ewan D.S. Wolff of the University of Wisconsin-Madison and Steven W. Salisbury of the University of Queensland, Australia, felt there was something "off" about that explanation. If these holes, and similar lesions on other Tyrannosaur jaws, were bite marks, they should be more ragged, and the jaw would appear more crushed. Also, bite marks were rarely consistent between specimens; however, the holes in the T. rex jaws were very consistent. They turned to a more mundane explanation.

In modern raptors, there is a parasite that causes something called trichomonosis. It attacks the jaw of these raptors, leaving a pattern of lesions that is very similar to that on the Tyrannosaur jaws. The scientists now suspect that the trichomonosis parasite, or something similar, was passed within Tyrannosaurs (there is no evidence of the disease in other dinosaurs). These creatures were known to attack, and even cannabalize each other, so the parasite could spread easily.

In Sue, the infection was very severe to drill holes in the jaw. It would have also created a film across the back of the dinosaur's throat. This would have made it very difficult for Sue to eat. This parasite could have easily lead to Sue's death, by starvation.

Credit: Science Daily: Was the Mighty T. Rex 'Sue' Felled By A Lowly Parasite?
See the Field Museum site for more information about Sue.


Lindsey said...

could you please point out where the holes are in her skull?

Ali Marie said...

The holes are on the lower jaw, near the back of the mouth. I've added arrows on the photo that point them out.

Does that help?
~Ali Marie