A new transforming turtle robot can explore treacherous regions where the land meets the sea--and may lead to future machines that navigate complex real-world conditions. Combining the best mobility features of an ocean-swimming turtle and a land-walking tortoise, the Amphibious Robotic Turtle (ART), described recently in Nature, can morph its limbs from turtlelike flippers to tortoiselike legs. "Most amphibious robots … use dedicated propulsion systems in each environment," says Yale University roboticist Rebecca Kramer-Bottiglio, who is the senior author on the paper. "Our system adapts a single unified propulsion mechanism for both environments: it has four limbs, and those limbs can transition between a flipper state for aquatic locomotion and a leg state for terrestrial locomotion." Each morphing limb is surrounded by a composite polymer material that is malleable when hot and stiff when cool.

The four-legged robot Dyret can adjust the length of its legs to adapt the body to the surface. Along the way, it learns what works best. This way it is better equipped the next time it encounters an unknown environment. The name Dyret (Norwegian for "The Animal") is an acronym for Dynamic Robot for Embodied Testing. "We have shown the benefits of allowing a robot to continuously adapt its body shape. Our physical robot also proves that this can easily be done with today's technology," says senior lecturer Tønnes Nygaard at UiO's Department of Informatics.

Sure, evolution invented mammals that soar 200 feet through the air on giant flaps of skin and 3-foot-wide crabs that climb trees, but has it ever invented a four-legged animal with telescoping limbs? Meet the Dynamic Robot for Embodied Testing, aka DyRET, a machine that changes the length of its legs on the fly--not to creep out humans, but to help robots of all stripes not fall over so much. Writing today in the journal Nature Machine Intelligence, researchers in Norway and Australia describe how they got DyRET to learn how to lengthen or shorten its limbs to tackle different kinds of terrains. Then once they let the shape-shifting robot loose in the real world, it used that training to efficiently tread surfaces it had never seen before. "We can actually take the robot, bring it outside, and it will just start adapting," says computer scientist Tønnes Nygaard of the University of Oslo and the Norwegian Defence Research Establishment, the lead author on the paper.

The drones rise all at once, 30 strong, the domes of light on their undercarriages glowing 30 different hues--like luminescent candy sprinkles against the gray, dusky sky. Then they pause, suspended in the air. And after a couple seconds of hovering, they begin to move as one. They've decided to head east. The drones at the front approach a barrier, and their tummies turn teal as they veer south.

Don't even worry about Dyret the robot. At first glance, the scrawny quadruped looks pathetic, as it struggles to walk without collapsing. But keep watching, and you'll see it start to improve--walking slowly, yet ever more proficiently. Dyret the robot is teaching itself to walk. Machines like Cassie the biped or SpotMini the robot dog are quickly mastering locomotion, thanks to line after line of meticulous code.