Dec 30 2010
Researchers at Northwestern University, USA announced that the squirting mechanism of electric fish could aid in developing alert underwater robots.
The black ghost knifefish generates weak electrical signal and detects any distortions in the signal. This capability enables it to swim and hunt in darkness in the Amazon River.
The black ghost knifefish swims by keeping its body firm and rolls out a long fin. Using its fin, the fish creates waves that move from its head to the tail, enabling it to swim forward. By creating waves that travel in the opposite direction, the fish can swim backward.
The scientists discovered that the black ghost knifefish could transmit two waves that crash with each other at the center of the fin. Results from the computer simulations showed that crashing undulations would shoot out jets of water, pushing the fish in vertical direction.
The researchers constructed a compact robot to imitate the fish. The robot comprised 32 electric motors fitted in a corkscrew pattern to propel its rubbery fin. The robot was then placed in a water tank along with beads and ignited them with a laser. The experiment was carried out to see whether the crashing waves in the fin squirted out the water.
Source: http://www.northwestern.edu/