On a late morning at the St. Louis Science Center, ecology educator Brian Thomas showed two elementary school students a fossil that looked like a very old, mangled piece of rock. It was a partial skull of a young Triceratops.
"Inside here is where the brain would sit," Thomas told the boys. "And it's not a very big brain."
The science center has two juvenile Triceratops skulls, dug up from northeast Montana, that a researcher at Washington University School of Medicine is studying to understand how the species developed in its lifetime.
Ashley Morhardt — a paleoneurobiologist at Wash U — and Thomas put the skulls through a CT scanner last fall, capturing detailed images of what the skulls look like inside to help imagine what the dinosaur's brain looked like. Studying the Triceratops' brain helps scientists gain a better understanding of what's common and what's unique across many different species over time.
Some features of the dinosaur's skull exist in many animals, including humans, Morhardt said.
"There are grooves for blood vessels, canals for cranial nerves," she said.
There are vast differences between mammal and dinosaur brains, however. The human brain, for example, is globe-shaped. Triceratops brains are tubular, which is the case for lizards, snakes and other reptiles. Thomas indicated on a model of a Triceratops brain that the olfactory bulb, which is responsible for sense of smell, is incredibly long.
"It's very thick, and it's in the back of the skull," Thomas said. "Depending on the size of that animal, it might have to run two or three feet to reach the sinus. Our nose is pretty much right next to our brain compared to them."
Researchers think that the Triceratops likely had a very good sense of smell. But its frontal lobe, the part of the brain that's associated with high-level thinking and reasoning, was not very developed, compared to humans.
"We've developed the capacity to build museums, do art, travel to space," Thomas said. "But we've lost some of the animal instinct that we used to have."
Triceratops also had a small brain, given its large body size. It likely would have been approximately a walnut and a half, Morhardt said. All of those factors suggest that the species was not very intelligent. But in its heyday, the Triceratops were as numerous as cattle and existed for much longer than humans have on Earth.
"We can joke about them being dumb, but really what mattered was that they were smart enough for what they needed to be to survive," she said.
Morhardt plans to publish her findings from the CT scans in the coming months. She will also be working with Thomas and the St. Louis Science Center to share that research with the public at a potential upcoming exhibit.
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