Quirks & Quarks

'Shocking' electric eel pack-hunting behaviour discovered in the Amazon

Pack behaviour is common in mammals like lions and wolves, but scientists had always believed electric eels were solitary animals — until now

Pack hunting is common among mammals like lions and wolves, but very rare among fish

Researcher C. David de Santana with an electric eel on a recent expedition through the Javari River in Brazil. (Douglas Bastos)

Researchers have spotted electric eels hunting in a group, working together to take down their prey that were packed together in a tight ball with a synchronized zap of electricity.

Electric eels — which are actually a type of knifefish instead of true eels — were thought to be solitary creatures. But a chance discovery in an Amazonian river is changing that idea. 

In 2012, students led by C. David de Santana discovered a lake deep in the Brazilian Amazon River basin filled with more than a hundred electric eels, many well over a metre long.

The researchers watched as those electric eels broke off into packs to herd small tetra fish into a tight ball, and then launched their coordinated attack.

The moment a pack of Volta's electric eels zaps their prey, stunning them into submission. They were observed doing this twice a day, on two different expeditions to the lake. (Douglas Bastos)

This species, Volta's electric eel, can produce shocks up to 860 volts, the strongest electric discharge of any animal on the planet. It's one of the 85 species of electric fish discovered by de Santana in the Amazon.

This discovery was recently published in the journal Ecology and Evolution. You can hear de Santana's interview with Bob McDonald at the link above.

Written and produced by Amanda Buckiewicz.


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