One Volta’s electrical eel– able to control small fish with an 860- volt jolt– is frightening enough. Now envision over 100 eels swirling about, unleashing collaborated electrical attacks.
Such a sight was assumed to be only the stuff of nightmares, a minimum of for victim. Researchers have long thought that these eels, a kind of knifefish, are singular, nocturnal hunters that use their electrical sense to find smaller fish as they sleep ( SN: 12/ 4/14). In a remote region of the Amazon, groups of over 100 electrical eels ( Electrophorus voltai) hunt together, corralling thousands of smaller sized fish together to concentrate, shock and devour the prey, scientists report January 14 in Ecology and Development
” This is extremely unforeseen,” states Raimundo Nonato Mendes-Júnior, a biologist at the Chico Mendes Institute for Biodiversity Conservation in Brasilia, Brazil who wasn’t associated with the study. “It goes to show how extremely, very little bit we understand about how electric eels act in the wild.”
Group searching is quite unusual in fishes, says Carlos David de Santana, an evolutionary biologist at the Smithsonian’s National Museum of Nature in Washington, D.C. “I ‘d never even seen more than 12 electric eels together in the field,” he says. That’s why he was stunned in 2012 when his associate Douglas Bastos, now a biologist at the National Institute of Amazonian Research Study in Manaus, Brazil, reported seeing more than 100 eels congregating and relatively hunting together in a pond in northern Brazil.
2 years later, de Santana’s group returned to the lake to make more detailed observations. The nearly 2-meter-long eels lethargically lay in much deeper waters during much of the day, the scientists discovered.
After confining the prey, smaller sized groups of about 10 eels unleash collaborated electrical attacks that can send surprised fish flying from the water. The scientists haven’t yet determined the combined voltage of such attacks, however 10 Volta’s eels shooting together could, in theory, power something like 100 light bulbs, de Santana states. The then powerless, floating victim facilitate pickings for the mass of eels. The whole ordeal lasts about two hours.
Up until now, such aggregations have actually been observed in just this one lake. De Santana thinks that group searching may be beneficial in other lakes and rivers with large shoals of little fish. Much of the eels’ range remains underexplored by scientists, so de Santana and coworkers are introducing a person science job with Native communities to identify more areas where lots of eels live together, he discusses. “There is still so much we do not know about these organisms.”