Tardigrades are weird and cool, and full of superlatives and contradictions. For just one example: the way tardigrades move is something special. They are microscopic and soft-bodied, but they don’t roam wildly with flagella like Euglena – they also do not have rows of oar-like eyelashes, like Paramecium to do. Tardigrades actually have eight small, stocky legs, with small claws at the ends.
New research into the physics of tardigrade locomotion has revealed that the way they walk has implications for robotics – and gave us all the chance to watch everyone’s favorite odd little space beast get its tiny , tiny groove. Meet my new favorite tardigrade, whom I named Mister Zoom:
I don’t understand why these awesome little wonders are described as “heavy” and “pushing”. Watch him walk around. He’s on the rails and going places. Water bears can put two body lengths per second behind them when they are really moving, which is like a human walking a seven minute mile. This is no small feat for these little feet. As an added bonus, you can definitely sync the above GIF to Deadmau5.
If this was a weird little valley for you, it’s no coincidence. Where the similarity to real bears ends is in the smooth, glassy gait of the water bear. Vertebrates have a cadence in the way they walk, and that cadence changes with the speed. Think about how a horse’s hooves change rhythm as it goes from a step to a trot to a gallop. But tardigrades don’t do that. They scuttle like spiders or centipedes do: instead of changing their pace, they just do the same thing, faster. “When vertebrates go from walking to running, there is a discontinuity,” explained study author Jasmine Nirody, Fellow of the Center for Physics and Biology Studies at Rockefeller University. “With arthropods, all walking patterns exist along the same continuum.”
While it’s definitely cute and even-y, the two-step tardigrade can actually teach us a lot; the researchers who captured Mister Zoom’s image were studying the movement patterns of water bears as a window into the evolutionary history of “pan-arthropod movement”. But studying how these little beasts move could actually be useful for robotics other than the supernatural horror that dances BigDog.
Because “soft-bodied walkers” are so rare, scientists may be able to draw inspiration from the tardigrade movement to better design robots capable of operating on a microscopic scale or on spongy terrain, or of standing. squeeze through small spaces without getting stuck.
“We don’t know much about what happens at extremes of locomotion – how to make an efficient little walker, or how soft-bodied things should move,” says Nirody. “Tardigrades are an important window in soft-bodied and micro-scale locomotion.”