Electric eels recorded for the first time hunting in packs

  • by
Electrophorus voltai - Electric eel

For the first time electric eels have been recorded hunting in packs and scientists believe that it is an extraordinary discovery. Dr. David de Santana from the Smithsonian National Museum of Natural History said, “Nothing like this has ever been documented in electric eels. Hunting in groups is pretty common among mammals, but it’s actually quite rare in fishes.”

Electrophorus voltai - Electric eel

Electrophorus voltai – Electric eel. Photo: L. Sousa.

Dr. de Santana watched eels in a lake in the Amazon rainforest having got there after a five day boat ride. The eels were observed lying still for most of the day and as twilight arrived the eels, who they believed were solitary, massed together to herd fish into a tight ball until they zapped them with 860 volts of electricity. The study has been reported in the journal Ecology and Evolution. They describe the attack in detail.

They reported that they saw the eels driving tropical fish into a “prey ball” at which point they were attacked. When the prey fish were electrocuted they jumped out of the water. They hit the surface stunned and motionless and were quickly swallowed by the eels. Sometimes opportunistic predators joined in to eat the tropical fish called tetras.

The high voltage discharge of electricity lasts for two thousand’s of a second and it is strong enough to paralyse the prey’s muscles. As the electric eels joined in taking their turn to discharge electricity it spread the load. They say that the eels formed a different subset when they attacked each time.

Each hunting event took about two hours, “and involved 5 to 7 joint high-voltage predatory attacks”. The eels that they observed have the scientific name Electrophorus voltai and are a fairly recent discovery. They discharge 210 V more than any other animal observed so far. The only location where this behaviour has been observed is in the Iriri River in the Amazon rainforest.

It is thought that this rare event takes place because there’s lots of prey with plenty of shelter for such a large number of eels. None of the locals had seen the eels attack like this. This species of eel is up to 8 feet long. Because the locals have not seen it happen before they think it’s a rare event.

SOME MORE ON MARINE WILDLIFE:

Blue lobster

Blue lobsters are 1 in 2 million

People ask whether blue lobsters are poisonous, real or rare and even whether they are expensive. Lobsters are blue because ...
Read More
Brown trout

Trout can become hooked on drugs

The Times reports that fish can become addicted to drugs like people. Dr. Pavel Horky, from Prague, in the Journal ...
Read More
Bottlenose dolphin

Male dolphins form alliances to get and keep their new female partner

I recently wrote about male dolphins who remember other males who did not come to their aid when they needed ...
Read More
Bottlenose dolphins can hold grudges against individuals who fail to assist when needed

Dolphins remember members of the group who help and those who don’t

STUDY - NEWS - COMMENT - ANALYSIS: Researchers say that male dolphins can hold a grudge because they can remember ...
Read More
Caleb Heikes a diver enjoys the company of an octopus who wanted a hug

Octopus wanted to hug female diver off Oahu, Hawaii

When I saw this photograph I thought of another similar situation. It concerns a Netflix documentary called My Octopus Teacher, ...
Read More
Angry octopus attacks Lance Karlson

Angry octopus attacks geologist while walking along the shore in Western Australia

In a highly unusual video captured by Lance Karlson, a geologist, the viewing public can see the angriest octopus attacking ...
Read More
Octopus

Octopus tentacles react independently to light

We know that octopuses are highly intelligent creatures and to that knowledge we can add a new discovery, namely that ...
Read More
Sea slug decaptitate themselves

Sea slugs voluntarily sever their own heads and regrow their bodies

Although sea slugs are uncharismatic - that's for sure - they have a monumental trick up their sleeve: they are ...
Read More