The biomechanical abilities of wild squirrels are coming into play as the Army studies ways to make robots more agile.

Researchers at the University of California, Berkeley, with Army funding, have studied how and when squirrels decide to leap and how they assess their probabilities of a safe landing.

By better understanding how squirrels learn the limits of their agility, scientists can better design autonomous robots. Incorporating this knowledge could help in the development of robots that can move nimbly across varied terrain, such as a collapsed building, during military missions or search and rescue efforts, or in assessing environmental threats, according to a news release from the Army Research Laboratory.

“Studying organisms’ behavior, like jumping squirrels, lets the engineering community ask fascinating questions about an autonomous agent trying to navigate an uncertain environment,” Dean Culver, program manager for complex dynamics and systems at the Army Combat Capabilities Development Command, said in the release. “For example, what stimuli cause learning? How does the interplay between structural compliance in a limb and surprises in an environment permit adjustments during a maneuver?” 

Enticing the furry critters with peanuts in a campus eucalyptus grove, university researchers and students studied cognition in fox squirrels. In their reports, the researchers quantified how squirrels learn to leap from a variety of stable and wobbly launching pads, how they reorient their bodies in midair based on the quality of the launch, and how they adjust their landing based on the stability of the final landing spot, the release said.

They found that, as expected, the flimsier or more compliant the branch from which the squirrels must leap, the more cautious they were. It took the squirrels just a few attempts to adjust to different compliances, the release said.

The squirrel research was supported by the National Science Foundation and the National Institutes of Health. It complements earlier Army-funded research at Berkeley that developed an agile robot, called Salto, that looks like a Star Wars Imperial walker and may be able to aid in scouting and search-and-rescue operations, the release said.