Make us your home page
Instagram

Today’s top headlines delivered to you daily.

(View our Privacy Policy)

Tyrannosaurus rex couldn't run, but it was a speedy walker

Fifty years ago, if you had asked the dinosaur experts, they would have told you that Tyrannosaurus rex was a speed freak — a giant predator that could outrun racehorses. The paleontologists would have pointed to its 3-meter hind limbs, leggy for even a big dinosaur, and described the creature as sprinting after prey at speeds of 40 mph.

But a better understanding of physics kneecapped the swift T. rex concept. Scientists, rather than looking at the bones alone, began to gauge dinosaur locomotion via models of skeletons and muscles. The picture that came into focus was a slower beast: T. rex, although no less of a predator, was certainly less fleet of foot.

A new report, published Monday in the journal PeerJ, refined just how fast the dino could go. T. rex wasn't much of a runner, the study authors say. In fact, it couldn't run at all. Instead, the animal speed-walked.

Thanks to its wide stride, T. rex would reach about 12 mph at its quickest hustle. "Most of us would have difficulty jogging to keep up," said paleontologist Phillip L. Manning, director of the Mace Brown Museum of Natural History at the College of Charleston, S.C. (Not that you'd want a dinosaur with 8-inch-long teeth as a walking buddy.)

Previous estimates of T. rex's maximum pace ignored weight loads on the animal's bones. The new study took those into account, Manning said, and the result was "a bit like putting a governor on an engine." The scientists asked the model T. rex to move as fast as it could. At a run, the model indicated that T. rex's bones would snap because its legs would buckle under its weight.

Unable to break into a sprint, it must have stepped its way through the Cretaceous Period.

But that doesn't mean a 7-ton T. rex, at a full-bore walk, was anything less than terrifying. Elephants also don't run, which is to say they never have all four feet off the ground, and have been reliably clocked at about 10 mph. That's fast enough to leave a lasting impression. "The joy of an elephant charging you, trust me," Manning said, "it's one of those trouser-filling moments."

John Hutchinson, an expert on evolutionary biomechanics at the University of London's Royal Veterinary College who has also estimated T. rex speeds, called this work a "very sophisticated computer simulation." The max estimate of 12 mph was in line with the low end of previous tyrannosaurus models.

But like all computer simulations, this one came with certain assumptions baked in, Hutchinson noted. The study authors assumed that the animal's muscles were optimized to be as strong as they could, figuring that bone strength was the T. rex's weak point. Hutchinson said he was uneasy about that assumption, noting that "we don't understand the principles that govern speed limits in living animals."

Manning acknowledged that the model could be improved: It gave a conservative estimate and did not account for features such as elastic tendons, which could bump up the T. rex's top speed.

At this point, Hutchinson said, such a consensus has built around T. rex behavior that the dinosaur "is quickly running out of questions" for scientists to answer. The locomotion of other dinosaurs presents more interesting scenarios, in his view. He is investigating how the earliest dinosaurs moved — animals the size of house cats that would have had to scamper away from giant land crocodiles or end up as lunch.

Manning is also curious about other dinosaur species, particularly the biggest of the bunch. "It's modeling a house walking across the plain," he said. "It is quite exciting."

Tyrannosaurus rex couldn't run, but it was a speedy walker 07/19/17 [Last modified: Wednesday, July 19, 2017 10:04am]
Photo reprints | Article reprints

© 2017 Tampa Bay Times

    

Join the discussion: Click to view comments, add yours

Loading...
  1. Black entrepreneur says city stiffing him on project after he endorsed Rick Baker

    News

    ST. PETERSBURG — A prominent African-American resident says his endorsement of mayoral candidate Rick Baker has led city officials to freeze him out of a major construction project along the historic "Deuces" stretch of 22nd Street S.

  2. Roosevelt Blvd closed at I-275 after truck hauling crane hits overpass

    News

    ST. PETERSBURG — A truck transporting a construction crane hit the Interstate 275 overpass at Roosevelt Boulevard Tuesday.

  3. Pasco students, 12 and 15, faces weapons, threat charges

    Crime

    Two Pasco County students from different schools were arrested Tuesday after one brought weapons onto campus and the other threatened a shooting, according to sheriff's deputies.

  4. It's official: Hillsborough high schools move to 8:30 a.m. start time, elementary schools to go earlier

    K12

    TAMPA — Hillsborough County high schools will start an hour later next year, beginning the day at 8:30 a.m. and ending at 3:25 p.m., the School Board decided Tuesday in a 6-0 vote.

    The Hillsborough County School Board has decided to end a compressed bus schedule that caused an estimated 12,000 children to get to school late every day. Under the new schedule, high schools will start at 8:30 a.m. instead of 7:30 a.m. Elementary schools will start at 7:40 a.m. and middle schools at 9:25 a.m. [Times files]