Dinosaur teeth reveal their eating habits

A team of scientists led by the University of Tokyo has found that scratches on dinosaur teeth could reveal what they used to eat. By employing a technique called “dental microwear texture analysis” (DMTA) – a scanning method devised to examine topographical dental wear and tear in microscopic detail – the experts inferred the feeding habits of large theropods, including Allosaurus and T. rex.

The researchers discovered that while some dinosaurs may have frequently crunched on hard bone, others had regularly eaten soft foods and prey. This technique opens up new research avenues in Paleontology, helping scientists better understand not only dinosaurs themselves, but also the environment and communities in which they lived.

“We wanted to test if we could use DMTA to find evidence of different feeding behaviors in tyrannosaurids (from the Cretaceous period, 145 million to 66 million years ago) compared to the older Allosaurus (from the Jurassic period, 201 million to 145 million years ago), which are both types of theropods,” explained study lead author Daniela Winkler, a postdoctoral fellow in Paleontology at the University of Tokyo. “From other research, we already knew that tyrannosaurids can crack and feed on bones (from studies of their feces and bite marks on bone). But allosaurs are much older and there is not so much information about them.”

The scientists studied 48 teeth – 34 from theropod dinosaurs and 14 from crocodilians (modern crocodiles and alligators). Surprisingly, the analysis did not reveal evidence of much bone crushing behavior in either Allosaurus or tyrannosaurids, although it was well-known that the latter ate bone. 

According to the researchers, there may be several reasons for this unexpected discovery. For instance, it could be that although T. rex was able to eat bone, it was less commonly done than previously thought. In addition, the team had to use well-preserved teeth, so it could be that extremely damaged teeth that could have provided evidence of bone crushing were excluded from the study samples. 

The investigation also revealed noticeable differences between juveniles and adults. “We studied two juvenile dinosaur specimens (one Allosaurus and one tyrannosaurid) and what we found was a very different feeding niche and behavior for both compared to the adults. We found that there was more wear to juvenile teeth, which might mean that they had to more frequently feed on carcasses because they were eating leftovers,” Winkler explained. 

“We were also able to detect different feeding behavior in juvenile crocodilians; however, this time it was the opposite. Juvenile crocodilians had less wear on their teeth from eating softer foods, perhaps like insects, while adults had more dental wear from eating harder foods, like larger vertebrates.”

Besides shedding more light on the behavior of various dinosaur species, this innovative technique could help scientists better understand the ancient environments in which these creatures lived. “From what we learn using DMTA, we can possibly reconstruct extinct animals’ diets, and from this make inferences about extinct ecosystems, paleoecology, and paleoclimate, and how it differs from today,” Winkler concluded.

The study is published in the journal Paleontology. 

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By Andrei Ionescu, Earth.com Staff Writer

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