The military’s robot army continues to evolve by leaps and bounds. Quite literally, now that some of the ‘bots have grown tails.

A research team at the University of California, Berkeley, funded in part by the Army Research Laboratory, have come up with a nifty new way to help robots stay upright and stable, even when making precarious hops and strides over difficult terrain. Inspired by the stabilizing powers that tails imbue in lizards (and, eons ago, dinosaurs) the group decided to add similar tails to their robots.

The precise angle at which a lizard flexes its tail, in response to the surface off which it jumps and the angle of its body, helps that lizard maintain control, even in mid-air, and land upright. The idea is to do the same for mechanical monsters.

“We showed for the first time that lizards swing their tail up or down to counteract the rotation of their body, keeping them stable,” Dr. Robert Full, a professor of integrative biology at UC Berkeley, said in a statement. “Inspiration from lizard tails will likely lead to far more agile search-and-rescue robots.”

Not to mention far more freaky lookin’ ones. In the video above, the team’s “Tailbot” mimics the tail control of a live Agama lizard. Without using its tail, the robot basically free-falls off a cliff. But once researchers add a gyroscope that can sense the robot’s body position and give feedback to the ‘bot’s tail, Tailbot is able to make ideal use of its new appendage — and demonstrate some impressive in-air agility.

Of course, this is only the latest bit of bio-inspiration to trickle over to military-funded robot design. Last year, scientists at MIT and the Florida Institute of Human and Machine Cognition developed the fastest ‘bot yet, courtesy of legs designed like ostrich limbs. Not to mention Darpa’s creepy, crawly robo-blob, inspired by the locomotion of octopi and mice, that recently grew six legs and learned to walk.

Video: UC Berkeley