An Albertosaurus, on display at the Royal Tyrrell Museum, shows heavy scarring from an altercation with another tyrannosaur. Injuries like this were common in tyrannosaurs. Sculpture: Brian Cooley
Bones can tell us a lot about the owner: What species was it? What did it look like? How old was it? But one of the most interesting questions to me is, what did it suffer from? Perhaps that’s a bit sadistic, but the injuries and diseases that dinosaurs suffered from can tell us a lot about how they lived, and in some cases, how they died.
The reason this field of science exists (palaeopathology – the study of abnormalities in ancient organisms) is because certain diseases and injuries affect the bones of an animal. If you’ve ever broken a bone, it would have healed itself with a distinctive lumpiness around the old break. After you die, that lumpy bone will be an instant identifier to a palaeopathologist that, at some time in your life, you broke that bone. It also contains clues as to how long ago it happened and even how it happened (such as a twisting injury, an impact, or repetitive stress). Diseases such as cancer, tuberculosis, arthritis, gout, and infections (to name a few) all affect the bone differently so that they can each be identified.
The most famous example of a (very) sick dinosaur is an Allosaurus (nicknamed ”Big Al”, and who had a whole BBC ‘Walking With Dinosaurs’ documentary about him) from Wyoming, USA. Palaeontologist Rebecca Hanna studied its bones and identified a remarkable 19 injured or ‘sick’ bones, which she was able to identify as resulting from a wide variety of injuries (fractures), infection, traumatic infection, and developmental abnormalities. These maladies were built up over the animal’s life but do not appear to have killed the animal. However, a very painful and badly infected middle toe probably slowed him down significantly and would have made it difficult to run down prey.
The terribly infected middle toe (arrow) of Allosaurus “Big Al” ballooned to three times its normal size and would have been extremely painful to walk on.
Broken bones (fractures) and bone infections appear to have been the most common problems that dinosaurs suffered from. There is also evidence that they had dental problems, tumours, arthritis, gout, developmental disorders (such as fused vertebrae) and healed bites.
So what does all this evidence tell us? Firstly, it paints a very real, ‘living’ picture of life during the time of dinosaurs. Second, some dinosaurs (especially, it seems, the tyrannosaurs) accumulated many injuries over their lifetime meaning they were tough enough to keep hunting and feeding even with a broken toe, or leg, or arm! Lastly, they tell us these animals lived extremely active, and often dangerous lives. Maybe that’s not too hard to imagine from looking at the teeth of a T. rex, but it’s something else to see the leg bone of a pitiful hadrosaur covered in gouges and puncture wounds from the teeth of one!
A hole (arrow) near the joint of a 70 million year old ornithomimid toe is identical to gout – a painful joint disease – in humans.
[I 'borrowed' the title of this article from Darren Tanke and Bruce Rothschild's compendium "Dinosores: an annotated bibliography of paleopathology".]
