From National Geographic:
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.
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