Strange Fish Uses Chin Like a Metal Detector

Peter's elephantnose fish has long been a laughing stock of scientists. But now, due to a new study by researchers at the University of Bonn, Germany, the hilarious looking creature's reputation might improve due to an astonishing attribute.

i-b513811af27ae16c9d7541f51f23ea59-Elephantnose fish.jpg
He's got the whole his nose!

According to the researchers' study, released in the Journal of Experimental Biology, Peters' elephantnose fish (Gnathonemus petersii) use weak electrical fields emitted out of their chins to scan the floor of the water and do so with amazing accuracy. The study shows how in total darkness the fish can sense the difference between a wide array of different materials and dead and living organisms, even when these objects are not right under their nose (so to speak) but farther away.

Sweeping its chin back and forth like a metal detector over the bed, the Peter's elephantnose fish looks for its favorite snack, dead nematocera larvae which are buried under the gravel and sand. Mutated muscle cells pulse electricity 80 times a second into the fish's surroundings and then the fish measures the electrical fields with sensors in its skin. The field is distorted by surrounding objects, allowing the fish to create an "image" of the surrounding terrain by sensing these distortions.

Listen to the noise of the fish emitting the signals

According to Professor Gerhard von der Emde, lead author of the study, the fish easily distinguished between different shapes underwater in pure darkness, such as a pyramids and cubes, and were even able to tell the difference when the shapes were non-solid, only frames of wire. The fish could also tell the difference between living and dead objects. According to Professor von der Emde, as quoted in this article from the Underwater Times,
"With its electric sense, it measures [the objects'] capacitative properties, i.e. their ability to store charges...Dead plants or animals cannot [store a charge].' Finally, the fish can tell the material objects are made of and how far away the object is.

All of this is probably possible because of the large brains these fish possess, even larger proportionately to their bodies than human beings. Hopefully they are not smart enough to figure out that everyone is laughing at them.


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Zooillogix is the latest addition to It's chock full of weird and wonderful stuff from the animal kingdom, like the Peter's elephant nose fish, which detects prey using electrical fields emitted from its chin.

PZ sent me over. i usually lurk, but ...
this is just lovely, and entertaining.
count me as a regular from now on. a regular lurker that is.

Best imitation of Jay Leno by a fish, ever.

PS: love the blog. Reading the archives with pleasure...

By kristen in montreal (not verified) on 22 Aug 2007 #permalink

I guess my question is 'which came first, sense of touch or electrical sensing nerves?' Is one just a variation on the other? I mean the similarity, in my opinion, is that they both use electricity to transmit information to the CNS. Just that the one is from further away but requires some similar processing [what was the starting power? is it (pressure/signal) increasing or decreasing? does it agree with my other senses? etc] albeit in different cells. Well, that's my guessing - are the nerve cells for detecting electric signals in water similar to the nerve cells that detect dermal pressures?

*by natural selection.

How does it eat the dead buried larvae with a chin like that? I guess it may root the sand up from the bottom with its leno-like protrusion and then filter out the edible bits, but yeesh.

Sounds like the star-nosed mole.

By John Emerson (not verified) on 23 Aug 2007 #permalink

Is this similar to the eleotrolocation used by the platypus? (Also, I think, the paddlefish, a species of elecrtic eel, and a couple other fish species)

Elephantnose fish navigate using electrical signals. An electrical field is created around the fish's body by modified muscles, and disturbances in this field are detected by receptor cells.

I am not sure if you have updated this but if you haven't then you should. If you read the article you will learn that these fish do not emit weak electrical fields (or anything else) from their chins. They emit the signal from the base of their tails and the receptors are in their chin.

It's Wednesday morning. I don't see his corporate backers fleeing him just yet, but the people who voted for him are turning away in disappointment.

Hello, I'm studing gnatonhemus petersii biology and ecology, i'll be so pleased if someboy can guide me to find more information about their habitat and species live. thanks