Doug Bonderud

Oct 23rd 2020

Dental Detectives: Dinosaur Teeth Deliver Details on Diets


While the existence of dino dentists might have improved saurian species’ quality of life (though, good luck getting a T-Rex to wait half an hour after a fluoride treatment before eating), great teeth aren’t a remedy for sudden asteroid impacts. But fossilized dinosaur teeth do offer a glimpse into evolutionary history, helping paleontologists understand dino diets and critical evolutionary impacts.

So, sit back and open wide, because we’re heading back to the Jurassic period for some dental detective work.

Tooth or Dare

Despite their historical distance, dinosaurs remain a compelling study scenario for humankind: What did they look like? What did they eat? And how did they evolve over their millions of years on planet Earth?

While this curiosity often results in a rallying cry to apply science and technological know-how to bring back a new generation of genetically-engineered dinos, this is both incredibly difficult and — as Jurassic Park made abundantly clear — dangerous. Thankfully, there’s a better and safer way to discover more about our prehistoric pals: fossilized dinosaur teeth.

Why? Because teeth are built with a bone and enamel combination that stays extremely well preserved. Dental archeologist Debbie Guatelli-Steinberg recently told NPR, “It’s kind of convenient because teeth hold so much information.” Not only does the shape and design of a dino tooth indicate its likely purpose, but calcified bacterial remnants and microscopic pitting can help identify what dinosaurs were eating — and how they ate it.

Peter Ungar, an anthropologist at the University of Arkansas, delved into this dental microwear analysis to discover what animals ate by analyzing what food did to their teeth. He also leaned into a great dental pun, calling this chomp-and-chew history a “foodprint.” Worth noting? When it comes to any dental detective work, Ungar makes it clear that teeth are typically adapted to the toughest part of an animal’s diet rather than what it eats all the time. As he put it, “If you eat Jell-O almost every day of the year, but sometimes you need to eat rocks … you want teeth that can eat rocks.”

Bite Me!

So, what did dinosaurs really eat? And how did they eat it? While the jagged, steak knife-edged chompers of large predators such as the T-Rex have been studied in-depth, that’s just the shallow end of the prehistoric pond.

Consider recent work from the University of Alberta, which examined the Saurornitholestes, a small meat-eating dinosaur. Potential recreations suggest that it looked sort of a like a goose with a terrifying dino makeover. Analysis of scratches left on fossilized teeth showed that the dinosaur likely bit down and then pulled its head backward when chomping on prey. According to Ryan Wilkinson, co-author of a paper that examined the Saurornitholestes and two similar, small meat-eating dinosaurs — the Dromaeosaurus and the Troodon — the motion is best described as “puncture and pull,” which helped these creatures grab onto prey and then tear off pieces of meat.

The team also discovered differences across these three similar species. Analysis of Troodon fossils showed differences in their smaller teeth, called denticles, suggesting that if they struggled while prey fought back hard, the thrashing motion could more easily break these teeth than those of Dromaeosaurus or Saurornitholestes. As a result, Troodon likely went after slower, smaller prey that was less likely to cause dental destruction.

Prehistoric Periodontology

Analysis of dinosaur teeth also provides critical insight into vertebrate evolution. While mammals were generally thought to have more complex tooth structures than their reptilian cousins, recent examination of fossils from Changchunsarus Parvus, a small herbivorous dinosaur found in China, found evolved tooth development in this early species of ornithopod. Not only did C. Parvus teeth show evidence of more advanced “wavy enamel” similar to that of later ornithopods, but they also developed a unique tooth replacement method that allowed continual recycling of teeth without disrupting the mouth’s overall shearing surface.

Meanwhile, work on preserved teeth and jaws from Captorithus Aguti — a reptile that lived before the age of dinosaurs — showed evidence of increased right-side jaw wear indicating the potential for functional brain asymmetry, which is a critical feature of vertebrate evolution at scale.

Food for Thought

Fossilized dinosaur teeth offer a bite-sized look into the history and evolution of Earth’s lizard overlords. Perhaps the same will be said someday of human molars and munchers left behind after our own apocalypse — but what will those looking back think of our fossilized fragments? Depending on the evolution of current diets and our ability to overcome general apathy toward dental service delivery, human history might offer the whole tooth — or nothing but the tooth.