for National Geographic News
The first rule of fish fight club is, remember who your rivals beat. The second rule of fish fight club is, remember who they lost to.
A new study shows that fish can watch their rivals face off and then figure out where they all rank compared to each other.
The fish were able to sort out the entire local hierarchy from seeing a limited number of fights between select pairs of their neighbors, the study showed.
This is evidence of surprising social savvy among these fish, Astatotilapia burtoni, a type of African cichlid. (Related: "Lost African Lake Spawned Fish Diversity 'Beyond Belief'" [May 4, 2005].)
The new findings will be presented in tomorrow's issue of the journal Nature.
Key to Survival
The fish's ability to gauge rivals' fighting strength is crucial to helping the animals figure out when to fight and when to flee.
The males of the species fight fierce battles over territories in lakes and rivers, since having a good plot is the key to scoring food and winning a mate. (Related video: "Cichlid Fish Mouth Fighting".)
"How many fights they win or lose ends up determining their reproductive success," said Logan Grosenick of Stanford University, who led the study.
"This results in a strong evolutionary pressure on them to use social information" to choose their fights wisely, he added.
A similar ability to learn a hierarchy from limited information has been shown in a few other animals, including monkeys, rats, and pigeons.
But those studies usually involved more artificial situations, where the animals get rewards from researchers for choosing the right answers.
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