It creeps like a worm, crawls like a snail, slithers like a snake and inches along like an inchworm. But the critter Lakshmi-narayanan Mahadevan and colleagues have designed is merely a filament of cylindrical hydrogel with a 2 mm radius measuring 2 cm long.1 By vibrating the glass plate on which the artificial animal rests and subjecting it to different oscillation patterns, the researchers induced the gel to execute different gaits.

"Our simple system suggests that there's an underlying unity in these seemingly disparate types of motion," explains Mahadevan. "Although snakes and snails are not related, locomotion can be explained by the same physical principles." The snail gait involves oscillations along the filament's axis. When the filament buckles and bends.1 laterally, it slithers; when it buckles out of the plane, forming loops, it starts to inchworm.

Many questions remain, says Stanford University's Joseph Keller. "To mimic nature more...

Interested in reading more?

Become a Member of

Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member?