Beautiful new video footage captures electric eel in the Amazon hunt in groups of over 100. Deadly packs then splinter to collectively deliver a propulsion shot that blows fish out of the water, a new study finds.
This is the first time such a group hunt has been seen in Volta’s electric eels (Electrophorus voltai), a type of knife fish already known to produce the strongest electric shock of any animal.
The video footage, described in the January 14 issue of the journal Ecology and evolution, was caught at a small lake on the banks of the Iriri River in Brazil. ‘It’s really amazing to find such behavior with 2.4, 2.5 meter eels [around 8 feet] long, “David de Santana, a zoologist at the Smithsonian National Museum of Natural History in Washington, DC, and co-author of the new study, told WordsSideKick.
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Mammals often work together to catch prey, but such behavior is relatively rare in fish, according to the new study. Prior to this discovery, scientists thought that electric eels were merely predators, usually attacking a single fish at a time.
The newly documented group hunting method involves up to 100 electric eels surrounding small tetra-fishes to form a ‘prey ball’ and then cast into shallower waters. Then some eel (between two and ten individuals) splinters away from the main group and moves closer to the ball to deliver a shock of electricity.
The synchronized shock is so powerful that some of the fish are blown out of the water and end up on the surface in amazement. They then float motionless and become an easy catch for the predatory poles.
“One individual eel of this species can produce a high voltage discharge of 860 volts. In theory, ten electric eels can therefore produce 8,600. That is a lot,” de Santana said. He had been shocked several times during his fishing studies and said the sensation was strong enough to cause ‘numbness’ in his arms. “It’s a very strong discharge, but the duration is very short,” de Santana said.
But de Santana has only been shocked once at a time. With the potential to take advantage of up to ten at a time, he recommends staying out of the water if you happen to run into a large group.
The first sighting of this behavior was “a kind of accident,” de Santana said. His colleague, lead author Douglas Bastos, a zoologist at the National Institute for Amazonian Research (INPA) in Brazil, was in the region in 2012 to study fish when he came across a town of electric eels and tetras coming out of the water. is shocked. . After making some initial recordings, the researchers decided to return to the same place in 2014, where they captured 72 hours of footage. In it, they documented the behavior five more times.
According to the researchers, hunting is probably less efficient if the eels encounter a group of prey that is attentive to their presence. By working together, the eel helps more powerful electrical discharges that can shock the prey from a greater distance.
The team suspects that the behavior is not common and is likely to happen only if the conditions are right. “Our initial hypothesis is that this behavior really occurs in places with high prey abundance and also with long-term shelter for multiple eels,” de Santana said. That means lots of fish and lots of nooks and crannies for the eel to live in. These conditions may exist only in the middle of the Amazon, he added.
Originally published on Live Science.