The acrobatic rodents called fox squirrels learn to leap from branch to branch with a mix of careful calculation and ‘parkour’, according to experiments that had them bounding through a simulated forest.

Nathaniel Hunt at the University of Nebraska Omaha and his colleagues provided free-ranging fox squirrels (Sciurus niger) with faux branches, each near a landing pad baited with peanuts. The researchers varied the branches’ flexibility and the distance between the branch and the pad. Then, they watched as the squirrels adjusted their leaps.

Analysis of more than 100 trials recorded by high-speed cameras showed that choosing a launch location is a trade-off: the further out on a bendy limb a squirrel goes, the shorter the leap to the next branch, but the bouncier the launch pad. Landing requires instant adjustments if the take-off branch is bendier than expected.

The researchers were surprised to see the squirrels bouncing off a vertical support with a “parkour leaping maneuver”, named after a form of urban gymnastics popular among humans. Although the parkour moves look fun, the actual goal is probably to modify horizontal velocity before landing.