Scientists Say Coral Trout Are Great at Picking Predator “Teammates”


Knowing who you work well with and the best time to put a plan into motion are pivotal parts of teamwork, yet only two species have both those abilities: humans and chimpanzees. Now scientists say that coral trout, also known as leopard coral grouper, possess the same level of intelligence when it comes to teamwork.

“Our results show that, like chimpanzees, trout can determine when a situation requires a collaborator and quickly learn to choose the most effective one,” lead author Alexander Vail told

The teamwork that the study focuses on is the relationship between coral trout and moray eels. The partnership revolves around hunting down prey fish. The trout does most of the work, chasing the fish into coral reefs, where the eel attempts to flush it out. If the fish decides to flee back into the open water, it is snatched up by the trout. If it remains in the reef, it will likely be consumed by slippery eel. Despite being different species, the two predators have learned to communicate with one another through movements such as headshakes and body positioning. What sets the trout apart is their ability to pick partners from among different eels. Scientists say that trout quickly learn which eels make better collaborators. In fact, coral trout proved to be better at this sort of distinction than even chimps.

Researchers used a relatively simple experiment to test the trout. The fish were presented with a piece of food out of their reach in a crevice, and were given a choice between recruiting two fake moray eels or attempting to reach the tasty morsel themselves. The eel props were operated by the researchers and varied in levels of efficiency. Scientists found that the trout consistently picked the eel that performed better, as well as knowing when help would not be necessary. In contrast, a similar experiment in 2006 that involved chimps proved that the primates were less capable than the coral trout.

You can see a demonstration of the experiment below:

“This shows that a big mammalian brain is not necessarily required to undertake these sophisticated forms of communication,” Vail, a marine biologist at Cambridge Univeristy, told the Daily Mail. “Although the brains of mammals are certainly larger than those of fish, size may not be all that matters, and we are still a long way from a thorough understanding of fish brains and the mental computation they may capable of.”

Researchers stressed that complex behavior does not always mean a complex mind. The team is still researching what makes humans, chimps, and now coral trout so good at teamwork. Of course, plenty of other species rely on teamwork as a fact of life, but Vail says that it may be that ecological need caused these three particular species to be picky about who they partner up with.

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