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Written by Sarah Kellett

In the warm tropical ocean around the Great Barrier Reef, the lionfish hunts. Venomous fins fan out to trap a school of smaller fish. The little fish look for an escape. But this lionfish is not hunting alone.

Lionfish as predators

As we grow up, we learn to share, take turns and cooperate. Now it seems lionfish use the same skills for a more deadly purpose. New research shows lionfish hunt better when they cooperate with other lionfish, and that they share the meal evenly.

Lionfish are predators and use their long, stripy fins to corner prey. While working on the Great Barrier Reef, Oona Lönnstedt from James Cook University in Queensland noticed something strange. “I did a lot of observations at night and this is when I noticed how they seemed to hunt together in groups, spreading out their large pectoral (side) fins almost like fishermen with their nets”

A maze-like aquarium

Curious about the behaviour, Oona went back to the lab and used a maze-like aquarium to observe how lionfish behaved when there was prey around and a second lionfish nearby.

If the first lionfish found prey, it would swim to the second lionfish and do a display. It would put its head down and wriggle its tail fin. Then it slowly waved one side fin, and then the other side fin. The second lionfish almost always responded by waving back and following the first lionfish to hunt. If the second lionfish didn’t follow, the first one would come back and do the display again.

The two lionfish worked together to hunt by using their big side fins to herd the prey fish into a corner. The first lionfish, the one that started the hunt, usually took the first bite. After that they took turns and shared the feast evenly. This behaviour even happened when the two lionfish were different species, for example when a zebra lionfish partnered with an antennata lionfish.

Hunting as a team was very successful. When they were together, each lionfish ate more than they did when they hunted alone. Oona and the team think this complex hunting behaviour might be one reason why invasive species of lionfish are causing problems in the Caribbean. Their teamwork technique is killing too many prey fish, threatening the whole ecosystem.

Share with us

Lions, hyenas, humans and moray eels also hunt cooperatively. Bees do a waggle dance to show other bees where to find flowers. What other examples can you think of?

More information

• In many places, lionfish are an invasive species – maybe these robotic assassins could help control them?
• Lionfish are great at cooperating – here are some games you can play with your friends to see if they’re just as good!

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