At schools and universities, students are taught that jellyfish are ‘primitive’ creatures way down the evolutionary ‘tree’. Unlike ‘more advanced’ marine creatures such as fish, jellyfish do not appear to be powerful swimmers. Lacking a backbone, their pumping action is slow and their forward movement often barely perceptible.

But is that a fair assessment?

Two recent studies of what jellyfish1 can do put things in a completely different light.

Unlocking the ‘secrets’ of jellyfish pumps

Medical researchers say jellyfish have just what they’re looking for.2

“Most pumps are made of rigid materials,” says California Institute of Technology researcher Janna Nawroth. “For medical pumps inside the human body, we need flexible pumps because they move fluids in a much gentler way that does not destroy tissues and cells.”

According to Nawroth and her co-researchers, jellyfish undulations “hold secrets” that may make possible vastly improved miniature pumps for medical applications and soft robotics. They have carefully studied the flows and eddies created by the pumping action of jellyfish, particularly a characteristic measure known as the Reynolds Number.3

“We’re very lucky,” said Nawroth. “The Reynolds numbers we see in the movement of jellyfish of different sizes and ages are in the right range as what we need for medical applications.”

There have been other insights too. For example, at a micro scale, jellyfish exploit the narrow layer of water adhering to their surface as they move—i.e., they “use it as [an] additional paddle at no extra cost.” What’s more, there is “a clever arrangement” of multiple pacemakers within the jellyfish body which fine-tune the pumping mechanism….

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