Tardigrades are currently the most interesting species of our age. The water bears are determined to be on the group of invertebrates but have features inspired by distinct groups, including the arthropods and the nematodes. The tardigrades are known to be the most invulnerable animal due to their ability to withstand the extremities of external force and the environment they are exposed to.

Tardigrades in Evolution

Tardigrade walking on 50 kPa gel, sagittal view.
(Photo: Lisset Duran et al.)

Tardigrades are microscopic and scale from 0.05 to 1.2 millimeters in length. Its physical features are similar to the anatomy of a caterpillar and woodlouse, with all the plumps and segmented curvatures. Tardigrades have eight legs with tiny claws varying from four to eight.

Tardigrade-like animals cannot walk, especially those with multiple legs that could only crawl as their way of movement. However, the water bears use all of their available legs to move across any environment where they exist, including desert dunes, undersea sediments, and underground soils. 

Rockefeller University experts recently conducted an observation to witness and analyze how tardigrades actually walk at the microscopic level. In the examination, it was found that the tardigrades have a very similar gait compared to the insects that have hard bodies, 500,000 times larger than their microscopic size.

The experts concluded that the tardigrades' ability of limbs and walking patterns is harnessed from either an evolutionary lineage or just a natural, anatomical advantage since there is no other possible way to explain how these microscopic creatures can walk the same as the insects, considering their size. 

Biology expert and author of the study Jasmine Nirody said in a Science Alert report that the tardigrades were observed to have a seemingly flawless movement pattern. The expert said that the tiny animals do not stumble through their environment contrary to popular belief, as it actually walks in a precise pattern.

Nirody expressed their interest in the evolutionary studies of tardigrades, as its locomotive strategy is nearly the same as the large insects such as the members of the arthropods.

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How Tardigrades Walk; Water Bear Movement Captured for the First Time

The walking pattern of the tardigrades was observed, and it was found that alongside their gaits, the water bears have unexpected characteristics and behavioral patterns.

They were found to be interested in some things and run towards them whenever they are in the mood. In some cases, they stall on walking and even stay in their position without moving. One of the important details the experts noticed is that the tardigrades walk while waddling the whole half of their body every second. 

Among the possible explanations why tardigrades have comparable locomotive skills with hard-bodied insects is that their evolution is linked with some of the insects that the experts specified in the study, including ants, fruit flies, and similar insects with a segmented anatomical structure.

If this theory is proven, it will contrast to the initial and most accepted hypothesis, in which tardigrades are not comprised of taxonomy. The first-time discovery on how tardigrades walk along with the captured video is published in the journal PNAS, titled "Tardigrades Exhibit Robust Interlimb Coordination Across Walking Speeds and Terrains."

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