Could T. Rex Swim? Here's What The Fossil (And Living) Evidence Says

We have good reason to suspect that Tyrannosaurus rex could swim. It’s hard to imagine, tiny-armed giant that it was, but it’s true.

The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.

Most animals can swim in some form or another regardless of whether they’re adapted for moving through water. The big question, really, isn’t could T. rex swim? It’s how did T. rex swim.

Could T. rex swim? The evidence

Sir David Attenborough took on the question of how T. rex might swim in Apple TV’s Prehistoric Planet. The series went in hard with briefly-aquatic T. rex, featuring it doing a kind of doggy paddle on the series posters. So, what evidence is there of this behavior?

We’ve found swim traces thought to be made by the claws of a two-legged dinosaur, like T. rex, scraping along the sediment. Some theropod swim traces were found in the Cameros Basin in La Rioja, Spain.

Hundreds of footprints were found at the site, but some of these were cut through by swim traces, indicating the water level rose and our walking dinosaurs had to get swimming. We’ve found similar marks (thousands of them, in fact) in Utah, so it doesn’t seem like swimming was all that rare.

 

Were you to look at a dinosaur that weighed in the region of 10 tons, you’d rightly think it's going to sink, not swim, but their bones tell a different story. They're filled with pneumatic cavities that were fed air from their respiratory system, and it would’ve made them much more buoyant in water.

“On the basis of this evidence, we think that T. rex would have been an excellent swimmer,” said Prehistoric Planet scientific consultant Dr Darren Naish in a YouTube video. “It would’ve used this behaviour to expand its feeding opportunities.”

Chances are T. rex was probably swimming too, then, but was it floating around like a duck, or bouncing sediment-to-surface like a hippo? It’s a good question.

How did T. rex swim?

Those pneumatic bones we mentioned would’ve made it hard for T. rex to swim underwater. Spinosaurus is believed to have been an adept swimmer, but it had dense bones that would’ve weighed it down in the water column while its paddle-like tail did the hard work.

We can look to some of T. rex’s closes living relatives for inspiration as to what it might have looked like in the water. Just check out this video of emus swimming.

Dependent on air for respiration, they keep their heads above the water while kicking with their legs. The general consensus is that T. rex wouldn’t have been far off a doggy paddle, kicking with its powerful legs while keeping its top half closer to the surface.

So, if you ever find T. rex taking a nap by some water, don’t choose a dinghy as your means of escape.