These Exotic Fish Use an Electric "Sixth Sense" to Communicate
Friday, June 22, 2018
Ghost knifefish use electricity as a sixth sense. Now scientists exploring tropical jungle streams have unearthed secrets regarding how these fish use electric signals to communicate in the wild. This work could shed light on how nervous systems in general process weak, ambiguous sensory data, which could help improve the design of bionic devices that interact with the nervous system.
Image of a juvenile of the brown ghost knifefish
(Apteronotus leptorhynchus)
Image credit: Guy l'Heureux.
Ghost knifefish generate electricity using a specialized tail organ derived from spinal cord neurons. Unlike their relative the electric eel, these freshwater fish are only weakly electric, not producing enough charge to stun or kill. Instead, these Latin American fish generate electric pulses to communicate with one another and produce electric fields around their bodies to scan their surroundings in the dark.
Scientists have been studying ghost knifefish in laboratories for decades. "A lot of scientists interested in cracking the code of what goes on with sensory signals in the brains of vertebrates work on electric fish," said bioengineer Malcolm MacIver at Northwestern University in Evanston, Illinois. "A lot of brain structures in fish are conserved in mammals because evolution doesn't like coming up with new things, so once you understand them in these weird, amazing fish, you understand a lot about how they work in mammals."
However, "we still know next to nothing about the secret lives of these fish in their natural habitats," said Jan Benda, a neuroethologist at Eberhard Karls University of Tübingen in Germany. To investigate ghost knifefish in their native waters, Benda and his colleagues first drove to the end of the Pan-American Highway in Yaviza, Panama, near the Colombian border. They next took a boat 40 minutes upstream the Chucunaque, the longest river in Panama, and walked 2 kilometers into the jungle to reach their destination, a narrow creek.
Electric fish "are really hard to observe visually," Benda said. "They are nocturnally active and they love to hide between rocks or in root masses."
More:
http://physicsbuzz.physicscentral.com/2018/06/these-exotic-fish-use-electric-sixth.html
