October 26, 2009--If it looks like a fish and swims like a fish, it could be a robot--such as the University of Bath's Gymnobot (pictured), inspired by an Amazonian knifefish.

Researchers worldwide are developing robots that look and act like aquatic creatures. That's because biomimetic gadgets--bots that take inspiration from nature--are often more efficient than their clunkier counterparts.

"In a fishlike fish, the whole of the animal is muscle--its propeller," said Gymnobot developer William Megill of the University of Bath, U.K. "That's not particularly conducive to putting in circuit boards."

To allow more room for cameras and other electronics, Megill's team took cues from the knifefish, which keeps its body rigid to sense electric currents in the water. In the same way, Gymnobot uses its lower, bladelike "fin" to propel itself through the water while the body remains rigid.

Megill and colleagues hope the bot can be used to study marine life near the shore, where a propeller would kick up too much sediment or get tangled in weeds.

--Rachel Kaufman