Tuesday, February 22, 2011

Tyrannosaurus as obligate scavenger?

A new paper in Plos One, from researchers at the Montana State University Museum of the Rockies, once again suggests that Tyrannosaurus rex was primarily a scavenger. The hypothesis has been around for some time and was originally put forth by Dr. John Horner, one of the authors on the new paper.

There has been much back-and-forth about whether T. rex was primarily a predator or scavenger. Just a month ago another study suggested that T. rex had to be a predator based on competition with smaller predators. (you can read a good critique of that paper here)

I am an arm-chair paleo-enthusiast so I don't know all of the intricacies of these studies. Likewise I don't really care whether T. rex was stricly a predator or scavenger (personal opinion is that it probably did a little of both as opportunities presented themselves). However, this new study raises a few questions for me.

Paleontologists have worked very hard to establish a well-supported relationship between dinosaurs and birds and yet the researchers in the paper use the mammal predator-prey relationships of the African Serengeti ecosystem as a model for comparison. While we know that dinosaurs were probably warm-blooded to some extent, their metabolic systems are not fully understood and they may have achieved that warm-bloodedness in a manner unlike mammals and more comparable to birds, or a metabolic system between that of more primitive archosaurs, like crocodilians, and modern birds. As a result, it seems to me that modern predatory birds may be a better model for understanding the context of predator-prey relationships and inferring feeding behavior.

I'm sure others have more questions regarding the methodology and conclusions of this paper. At any rate, any good research paper should generate as many questions as it addresses. While I doubt there will ever be a conclusive determination made regarding the feeding behavior of Tyrannosaurus rex, this and other future papers will generate new ways of thinking about fossil evidence.

photo: T. rex vs. Triceratops photo by Casey Tucker, Wild Auk Photography