Why Cockroaches Are So Hard To Squish

Have you ever stomped a roach, just to have it skitter away unscathed? Or seen one disappear into an impossibly small crack?

Now scientists have figured out how they do that, and the results are terrifying.

The American cockroach (Periplaneta americana, aka “the big ones”) can squeeze through a crack the height of two stacked pennies in about a second—a fact newly discovered by two brave scientists who are probably still seeing roaches squeezing under the doors of their nightmares.

No door will stop them: American cockroaches can squeeze through a space just three millimeters high. [Photo credit from Tom Libby, Kaushik Jayaram and Pauline Jennings. Courtesy of Polypedal Lab UC Berkeley]

Not only can roaches fit through tight spaces by flattening their flexible exoskeleton and splaying their legs to the side, the researchers found, they can keep running nearly as fast while squished, the team reports Monday in the Proceedings of the National Academy of Sciences. (In roach terms, top speed is 1.5 meters, or 50 body lengths, per second. Scaled up, that’s equivalent to a human running 200 miles per hour.)

Robert Full and Kaushik Jayaram at Berkeley built tiny tunnels and used a roach-squishing machine to test the animals’ limits. (No roaches were harmed—Full says “we only pushed them to 900 times their body weight, and they could still do that without being hurt.” In fact, they ran just as fast afterward.)

“We find them just as disgusting and revolting as everybody else,” Full says. But he also thinks they’re amazing, and is designing roachy robots that can squeeze and scuttle just like the real thing. The robots take inspiration from roaches’ jointed exoskeletons, with a design similar to folded origami.

A new compressible robot, nicknamed CRAM, is inspired by the flexible yet tough cockroach. [Photograph by Tom Libby, Kaushik Jayaram and Pauline Jennings. Courtesy of Polypedal Lab UC Berkeley]

Full sees roaches and other arthropods—insects, spiders, and the like—as the next big thing in robots inspired by nature. Unlike other soft robots inspired by worms or octopuses, insect-bots with hard exoskeletons and muscles could run fast, jump, climb, and fly, while still remaining flexible.

“We know that cockroaches can go everywhere. They’re virtually indestructible,” Full says. For roaches, being able to scuttle quickly through small spaces has allowed them to spread into virtually every habitat imaginable and outrun their competition. Other insects probably have their own versions of these super-squishing superpowers, too, he says.

Discuss this article

Newsletter

Never miss a Nat Geo moment

Your email address
Submit