To create robots, researchers highly rely on observational data that describe how species, from which they derive their experiments, move. The development of underwater robots are usually based on the study of jellyfish and lampreys because these animals are known to have highly efficient and smooth movements under the water.

Jellyfish and lampreys have always been thought to move by pushing themselvs from the water to propel forward. However, researchers recently discovered that is not actually the case as the sea creatures actually pull water towards themselves in order to move.

The new discovery of the experts could help enhance scientific understanding and open up new advances in the technology of underwater vehicle development, alongside other technical applications.

John Dabiri, co-author of the study and a professor of mechanical engineering and civil and environmental engineering at Stanford said that for almost a century, it has been assumed that imitating how efficient swimmers move means looking for ways to create high pressure mechanisms to push water backwards.

"Now we realize we've had it backward, and so the search is on for ways to generate low-pressure suction to achieve more efficient underwater propulsion," he added.

John Costello, one of the study authors and a jellyfish expert from Providence College said that the results of the new study demonstrate the process chosen by evolution to enhance distance-for-effort in underwater species. He explained that flexible structures are what enable underwater animals to move through fluids, and the recent findings pave the way to comprehending the reason why evolution assembled upon specific bending patterns.

Recent researches in the field of engineering and biomechanics usually focus on high pressure propulsion. The discoveries of the study, which targeted low pressure propulsion, could help improve the designs of submarines to make them more energy efficient.

Dabiri said that low pressure can be developed in many ways like body rotation to make way for whirling vortices where regions of low pressure are found within the vortices' center.

Brad Gemmell, co-author of the study from the University of South Florida said their study proves that some of the most highly efficient swimmers use low pressure movement and enable forward pulling of the body with suction. Therefore, experts may have to rethink about the swimming mechanisms that animals have acquired through evolution, as well as the manner in which vehicle designs should be approached in the future.

The study was published in the journal Nature Communications on Tuesday, Nov. 3.

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