UT Expert Helps Find Evidence That Prehistoric Crocs Ate Small Dinosaurs

Prehistoric relatives to crocodiles and alligators fed on tiny dinosaurs, according to fossil evidence discovered by a team of researchers, including a UT lecturer.

Stephanie Drumheller feeding a partial cow hind limb to a group of American alligators at the St. Augustine Alligator Farm in Florida. She was collecting bite mark samples from different species of crocodylian on cow and pig limbs.

Stephanie Drumheller, a 2005 graduate and lecturer in the Department of Earth and Planetary Sciences, analyzed bite marks on some seventy-five-million-year-old dinosaur bones that were collected in southern Utah in 2002.

What the team of paleontologists found was unusual. In one of the bones, there was a remnant of a crocodyliform tooth, similar to one from today’s alligators and crocodiles.

Drumheller studies modern crocodylian bite marks by comparing them to ancient ones to learn about the past. The discovery of a crocodyliform tooth in a dinosaur bone was a rare, and welcome, one.

“Crocs shed teeth throughout their lives, so finding isolated teeth is fairly common. However, finding a tooth still stuck in a bite mark is very rare,” Drumheller said.

During the time of dinosaurs, Utah was a warm and wet place, dominated by rivers and lush with greenery. It was home to several familiar dinosaurs, such as the tyrannosaurid Albertosaurus, but the bones the team of paleontologists unearthed belonged to at least three small two-legged herbivores known as hypsilophodontids. The researchers estimated these tiny dinosaurs weighed anywhere from 28 to 46 pounds.

Although the bones were small, the marks left by the predator were startlingly clear. After examining the indentions, the paleontologists estimated that the crocodyliform was anywhere from three to six feet long.

Femur with tooth.

The team expects their findings will shed new light on the relationship between the reptiles.

“We often think of dinosaurs as the dominant animals at the time, but these fossils are telling us that crocodyliforms would have been a real danger to anything living near the Cretaceous waterways of Utah,” Drumheller said.

Drumheller and her colleagues, Clint Boyd of the South Dakota School of Mines and Technology and Terry Gates of North Carolina State University and the Natural History Museum of Utah, will continue looking for additional traces of crocodyliform feeding by studying fossils from many time periods.

The team’s findings are creating a buzz in the science world and have been talked about on National Geographic online, NBC News, and LiveScience.com.

Drumheller will report the findings, among other things, in an upcoming UT Science Forum on April 12.

The fossils, collected from Bureau of Land Management land, are being held at the Natural History Museum of Utah.

Read the team’s detailed findings in the journal PLOS ONE.

C O N T A C T :

Christine Copelan (865-974-2225, ccopela7@utk.edu)

Amy Blakely (865-974-5034, ablakely@utk.edu)