A tardigrade goes for a walk on 50 kPa gel, sagittal view.
It’s not every day you get to watch a tardigrade go for a stroll on its eight stubby legs. Luckily, new research has captured their walk on video – and it’s adorable.
Known for their incredible toughness, these tiny creatures are able to survive everywhere from mud volcanoes to the deep sea to outer space. Now, a study has revealed how they move around – showing that their gait closely resembles insects 500,000 times their size.
“Tardigrades have a robust and clear way of moving – they’re not these clumsy things stumbling around in the desert or in leaf litter,” says Jasmine Nirody, a biophysicist at the Rockefeller University.
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Tardigrade walking on gel of 10 kPa stiffness.
Nirody co-authored the new study in PNAS, in which she and her colleagues observed tardigrades walking across a variety of different surfaces, from sediment to sand to soil. At a leisurely pace, tardigrades walk about half a body length per second, but when they really get going they lope along at two body lengths per second.
Interestingly, while vertebrates have a distinct gait for each speed, tardigrades don’t – they resemble insects in that their patterns of steps don’t change as they speed up.
“The similarities between their locomotive strategy and that of much larger insects and arthropods opens up several very interesting evolutionary questions,” Nirody says.
A tardigrade goes for a walk on a gel of 50 kPa stiffness.
Perhaps tardigrades may share a common ancestor with insects and should be classified within the panarthropod clade, the study suggests, or perhaps they independently evolved the same walking strategies.
“If there is some ancestral neural system that controls all of panarthropod walking, we have a lot to learn,” Nirody says.
“On the other hand, if arthropods and tardigrades converged upon this strategy independently, then there’s much to be said about what makes this strategy so palatable for species in different environments.”
Tardigrade struggling on smooth glass.