Jurassic Slow-Poke: The T-Rex May Not have been Able to Run at All

 Who can run faster: A Tyrannosaurus rex, or Jeff Goldblum? Researchers are now putting their bets on Mr. Goldblum, in light of a new finding that might settle the debate regarding whether or not the tyrant lizard king could run fast to begin with — or at all, for that matter.

This finding started with a study aimed at coming up with a formula for predicting how fast a given animal can run. Ecologist Myriam Hirt, with the German Centre for Integrative Biodiversity Research, found that using the resulting formula, there appears to be a sweet-spot in a species’ mass that determines how fast the animal can go: if it’s too small, the creature won’t be able to cover a large enough stride to exceed a particular speed; too big, and they run out of energy early from the simple act of accelerating.

For instance, the fastest land animal — the cheetah — can accelerate from zero to sixty in under three seconds, because it is sits in a sort of Goldilocks zone in terms of its size: it’s big enough to have a long stride, but also light enough to be able to accelerate quickly and efficiently.

It also turns out that the formula can also be applied to extinct species, such as dinosaurs. The top speed of a T-rex has been long debated: visually, the creature looks like it is built for running, with its bird-like gait and horizontal profile. But research into how the T-rex’s skeleton would hold up at high speeds found that the stresses involved would severely limit how fast it could run.

A separate study conducted at the University of Manchester, using a similar technique, found that the T-rex was limited to about five meters per second, or 18 km/h (12 mph).

"The muscles need to be able to generate sufficient power to allow high-speed locomotion, but at the same time the skeleton has to be able to cope with the loads generated by the high speed," explains Professor William Sellers, from Manchester’s School of Earth and Environmental Sciences "…This is where it fails. T-rex’s skeleton is simply not strong enough for running locomotion."