The Argentinosaurus was the largest of the sauropods, dinosaurs with long necks and tails, relatively small heads and thick, stout legs. It weighed more than 80 tons and was 100 feet long. Given its mass and size, there have long been questions about whether the dinosaur was as large as some experts suggested and how it physically could have moved such a titanic frame.
That uncertainly has persisted in part because so little of the Argentinosaurus has been recovered. Scientists have been left to deduce the size and mobility of the dinosaur based largely on a handful of vertebrae, ribs and leg fossils.
“It is frustrating there was so little of the original dinosaur fossilized, making any reconstruction difficult,” Phil Manning, who collaborated on the project and heads Manchester’s paleontology research group, said in a statement detailing the research.
To tackle that challenge, the researchers in Manchester and Argentina began by using a laser scanner to create a detailed 3-D image of the dinosaur. They then used computer-modeling software designed by Sellers to reconstruct how the giant animal probably moved along the ground. The modeling took into account factors such as body mass, muscle size, shape and bone structure.
“This is science, not just animation,” Manning said.
Their verdict: As far as the physics go, Argentinosaurus was a “perfectly competent dinosaur,” Sellers said. “There’s nothing mechanically that would stop you having an 80-ton dinosaur built like this.” He said it could have trudged across the landscape foraging vegetation on the ground or from the tops of trees.
But it wasn’t an easy existence.
“It was a relatively slow beast,” Sellers said, noting that the dinosaur’s top speed was probably about 5 mph. “As you get bigger, you start running out of the force you need to move. This animal would find things like getting up off the ground very difficult. I hate to think how it would do things like mate. That would be a very delicate operation for it, because it was so large.”
Sellers and his team are the latest in a long line of researchers, experts and animators who have tried to solve the riddle of how dinosaurs actually traversed the Earth.
Kent Stevens, a computer scientist and expert in dinosaur locomotion at the University of Oregon, said in a lecture last year that doing “good science” on the topic is difficult and tricky, mainly because researchers must figure out “a behavior that’s no longer observable” using mostly circumstantial evidence.
In an interview Wednesday, Stevens said the study done by Sellers and his team certainly qualifies as sound science.
“These guys are going in the right direction,” he said. “They’re being very careful about how far they try to push their data. . . . As they incorporate more sophistication into their models, they will be able to make more and more specific predictions.”
Stevens also said that while the simulation accompanying Wednesday’s study might look simplistic or rudimentary to casual observers, the underlying science is anything but simple.
“They are not trying to make a “Jurassic Park”-type simulation. . . . The public quite often has their expectations set by what they see in cinema,” Stevens said. “If you just look at the animation, you might say it looks awkward, but that’s not the point. One of the primary things they found is that, yes, there could be an animal as heavy as this.”
Sellers said he and his team tried to begin their undertaking with no preconceived notions and tried to rely only on the data available.
“The difference between what we’re doing and some other people are doing is that we don’t use as a starting point an assumed way that this animal would have moved,” he said. “We can’t be 100 percent certain that we found the best answer. . . . But we’re getting close.”
The Manchester team plans to detail how smaller dinosaurs would have moved through the prehistoric world.
“Our next target is probably a triceratops,” Sellers said. “It has short front legs and long back legs. It’s going to have a really peculiar way of walking.”