Did Tyrant Dinosaurs Dine on One Another?

NEW YORK - MAY 10:  A full size cast skeleton of a Tyrannosaurus rex is displayed at the new exhibit 'Dinosaurs: Ancient Foss
NEW YORK - MAY 10: A full size cast skeleton of a Tyrannosaurus rex is displayed at the new exhibit 'Dinosaurs: Ancient Fossils, New Discoveries' at the American Museum of Natural History May 10, 2005 in New York City. The exhibit, which will open to the public on May 14 and run to January 8, uses recent fossil finds, computer simulations and life size models to trace changes in the thinking about dinosaur biology over the past two decades. (Photo by Spencer Platt/Getty Images)

It is almost inevitable that any article discussing dinosaurs (and often even those covering other prehistoric animals) will mention Tyrannosaurus rex. It's a true touchstone, something that can be instantly recognized by almost any reader no matter how young or old and provides a reference for the point being made. As someone who actually works on tyrannosaurs and their behaviour this can actually be frustrating: I want to be in a position to communicate how interesting and unusual these great carnivores were and yet they are such a cultural icon, you have a mountain to climb in terms of getting over what people think they know about them.

The last members of the tyrannosaur group were around at the end of the reign of the dinosaurs and were also the biggest. Called tyrannosaurines these included the Asian Tarbosaurus and Zhuchengtyrannus (the latter of which I named in 2011) and a number from North America including Daspletosaurus, Albertosaurus and, yes, Tyrannosaurus. Palaeontologists have recovered more good skeletal material of some of these animals than any other large predatory dinosaurs and they have been the focus of huge amounts of research. As a result we probably know more about T. rex and its kin than perhaps any other dinosaur group.

This makes them superb research models -- if we already know a lot about them, it's easier to fit in new discoveries and put them into the correct context. For example, unlike all other carnivorous dinosaurs, we do have direct evidence for both scavenging and predation by tyrannosaurines. It's really pretty likely that other big carnivores like the allosaurs and spinosaurs similarly engaged in both, but we can be 100 percent sure when it comes to the big tyrannosaurs. Evidence like this primarily comes from bite marks -- when feeding or attacking, the teeth of these animals would scrape across the bones leaving sets of scores and punctures in the surface that can be used to show how they were feeding.

There are in fact not a huge number of bite marks and as a result, every new specimen can add quite a lot more information to the pool and tell us something new. I'm currently looking for funds to travel to Canada and work on an extremely exciting and potentially rather important tyrannosaurine skull that could reveal much about their behaviour.

I've already published quite a bit on dinosaur feeding and predation and indeed on tyrannosaurines (you can download my papers here). I'm also blogging about the project on the host site and I can answer questions people have about the project and dinosaur behaviour. I can't think of another thing like it available in the sciences right now and as a big supporter of science outreach and communication, this works wonders.

But what will this project be about? Obviously the final results are not known, or I wouldn't be looking to do the science, but there's obviously an exciting premise to this. Mentioned above, Daspletosaurus is one of the big tyrannosaurines, clocking in at around 8 meters in length and a couple of tons. Like the other big guys, this had a proportionally large head, big teeth, a bull neck and rather long legs, but offset with those little arms and two fingers on each hand. There are some really great specimens of Daspletosaurus that have been found, but I have been offered the opportunity to work on one that is unique.

It is a skull an lower jaw that show a number of bites marks across the surface that can be clearly referred to another tyrannosaurine (no other animals of such size and bite power were around at the time). The most credible candidate at the moment is actually another Daspletosaurus -- it looks likely that one was eating another in a case of cannibalism! Oddly enough there is a Tyrannosaurus toe bone with a bite from another, so this is probably not the first ever case of tyrannosaur cannibals, but it does contain numerous marks that means that there's a lot that can be gleaned about patterns of bites and feeding habits.

Similarly, almost every bite mark we have is from a true huge tyrannosaurine, and while obviously a hefty animal, Daspletosaurus was rather smaller than Tyrannosaurus and Tarbosaurus. That provides a nice opportunity to see if there were any changes in style as they got bigger, Daspletosaurus was well equipped to bit into and chew up bone, but did it take a different feeding approach to those that came later with still more powerful jaws?

Collectively then, this project can help us learn a great deal about the feeding and behaviour of the tyrannosaurines. It will place the activities of beasts like Tyrannosaurus in context and provide new data on the feeding (and yes, quite probably cannibalistic) behaviour of Daspletosaurus. I hope you are as excited by this as I am, and there will be much more coming on this project on the web.

Dr David Hone is a palaeontologist at Queen Mary, University of London, UK. You can read more about his project here, and you can also buy project t-shirts and other items here.