Robotic Ghost Knifefish Is Born

Researchers at Northwestern University have hatched a robotic replica of the ghost knifefish, an amazing sea creature with a ribbon-like fin, capable of acrobatic agility in the water.

The fish is distinctive in its ability to move forward, backward and vertically, but scientists didn't understand its vertical movement until the creation of its robot replica, GhostBot (shown below). They now know its vertical propulsion is caused by two waves moving in opposite directions, crashing into each other. One wave is pushed from the tail end, the other from the head; the two waves then meet in the middle, and create a mushroom cloud-like jet that pushes the fish upward.

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