You might be able to outrun a Tyrannosaurus Rex, if you’re a peak athlete. Keep note of that. You almost certainly can outmaneuver them. Those are the key takeaways that Wired wants you to have after reading “How to Outrun a Dinosaur.“

There’s a lot more depth in there for a game designer, homebrewer, or storyteller.

Three years ago the biologist Myriam Hirt, who studies animal movement at the German Centre for Biodiversity Research, asked a seemingly simple question: Why is it that the biggest, most powerful animals—the whales, elephants, and rhinoceroses—are not the fastest, while the smallest—the mice, minnows, and millipedes—are some of the slowest? Is the implication that there is an optimum size for speed?

The answer, Hirt found, is yes. If you were designing an animal for speed, that animal should weigh approximately 200 pounds. A bit heavier for a swimmer, and a bit lighter for a flyer.

Wired, How to Outrun a Dinosaur.

The T Rex has a speed of 50 in Dungeons & Dragons. That’s too fast for the mass of meat with jaws of death. Smaller dinos and lizards should probably have higher speeds. The Ripper Lizard is getting an update as this story is getting written.

The speed of 50 might make sense if the primary time in D&D that speed is used is to determine distance running. But it is not. Speed most frequently comes up in combats in six-second chunks of time. Beasts and Monstrosities with high speeds should be the ones that accelerate and burst forward — cheetahs, lions, and Deltadromeus. Even the velociraptor should be average-to-athletic human sprint speed-ish.

That also brings up a key point. A D&D character is supposed to represent, in general, above average athletes. There’s no direct tie-in between Strength, Dexterity, or Constitution and speed. Most races get a 30, some get a 25, rare ones get 35, and even rarer are the few that fly or swim.

There are three things we should do with the knowledge from that Wired article;

• Centerline most speeds to better represent reality in non-magical creatures.
• Add line in the description that addresses distance traveled by unencumbered and encumbered beasts of burden.
• Create a quick and easy way to avoid getting run down by a dinosaur.

That last bullet doesn’t take a lot of work. When in a chase scene use opposed Dexterity checks (Acrobatics or Athletics or Sports could apply) when the chaser is within Reach of the chasee. A success would permit an attack/shove/grapple, if the action economy makes sense. If not, let the chasee take half their movement as a reaction as long as they are able to, and do, significantly change direction.

Any creature that has magical influence on their speed can operate as normal.