Tardigrades are known to be champions of survival in the most extreme conditions. They can survive in a nuclear reactor and even in outer space, wear armor made of DNA strands and are capable of falling into suspended animation. However, these are far from all the amazing abilities of tiny creatures. Have you ever paid attention to how they move?
After all, they are one of the few animals with such soft bodies that can walk, and they are also one of the smallest animals with legs known to science. "One of the coolest - and at first most unexpected - features of tardigrades that we were surprised to find was how good … they are at it," - wrote on Twitter, mechanical biologist at Rockefeller University Jasmine Nirodi.
She noted that tardigrades have "a correct gait, remarkably similar to that of much larger animals!"
Nirodi and her colleagues recorded the walking tardigrades, Hypsibius dujardini, to analyze their gait and leg coordination, with surprising results. “We didn't force them to do anything. Sometimes they were relaxed and just wanted to walk on the substrate,”said Nirodi. “On other occasions, they saw something they liked and literally ran to that object.”
P. S. We have * plenty * more videos, and somehow they are all this cute + cool
- Jasmine Nirody (@jasnir_) March 22, 2021
The team allowed the tardigrades to walk on different surfaces, finding that their gait was very similar to that of insects, despite the fact that the two groups were incredibly different in size and arranged in very different ways.
The team also recorded how the little creatures tried to walk on smooth glass (they didn't get very far) and on gels with two different levels of stiffness to see if this would affect gait.
"We found that tardigrades adapt their movements to a 'galloping' coordination pattern when walking on softer surfaces," the team wrote in a new article. "This strategy has also been observed in arthropods, which allows it to move efficiently over flowing or granular substrates."
Why tardigrades are so insect-like is still an open question. Researchers are not sure whether they could have had a potential common ancestor, or whether the walking trait developed separately and independently in both organisms - this is the so-called convergent evolution.