By James Gamble via SWNS
Marlin rapidly lights up their stripes to coordinate their group attacks, revealing new research.
German scientists discovered that lightning-quick predators change the color of their stripes to indicate to others when they intend to attack.
The marlin – some of the fastest animals on the planet – was already known to be able to change color, though this marks the first time they have been found to coordinate attacks by utilizing color changes.
Striped marlin, though smaller than other marlin species, remain one of the ocean’s top predators.
Though they can measure up to 12 feet long and weigh up to 450 lbs, they are still some of the fastest animals on the planet with a top swimming speed of more than 50mph.
When hunting schools of fish in groups, individual marlin take turns attacking their prey whilst the others follow on behind.
But now, a study published in the journal Current Biology has answered how they know whose turn is next without getting in each others’ way or injuring each other.
The key, according to researchers at the Humboldt University in Berlin, is rapid color changes.
In observing group hunts from above using drones, marine scientists were able to observe the marlin and identify when color changes in their stripes occurred.
Dr. Alicia Burns, a research fellow at Humboldt University and lead author of the study, explained: “We documented for the first time rapid color change in a group-hunting predator, the striped marlin, as groups of marlin hunted schools of sardines.
“We found that the attacking marlin ‘lit up’ and became much brighter than its groupmates as it made its attack before rapidly returning to its ‘non-bright’ coloration after its attack ended.”
Dr. Burns’ team used drones to film the marlins for their study – giving them a new perspective on how they move and hunt.
Whilst examining the footage, the researchers noticed something unexpected: the stripes on individual marlins got obviously brighter as a fish moved in for an attack.
As they swam away, they noticed that these stripes dimmed again, and questioned whether the fish were changing colors to communicate with one another.
To explore this question, the researchers analyzed a dozen high-resolution video clips, each containing two separate attacks on a school of sardines by two different marlins.
They also compared the stripes on the two attacking marlins to a randomly chosen marlin that wasn’t attacking.
Their analysis confirmed that the predatory fish rapidly change color, suggesting this the color change might serve as a reliable signal of an individual’s motivation to go in for an attack.
“Color change in predators is rare, but especially so in group-hunting predators,” Dr. Burns said.
“Although it is known that marlin can change color, this is the first time it’s been linked to hunting or any social behavior.”
The team’s discovery suggests marlins have more complicated communication channels than were previously been suspected.
They suggested the colour changes could even serve a second purpose of confusing their prey.
The researchers now aim to further explore this idea whilst answering further questions, such as whether marlins use their impressive colour-changing abilities in any other contexts.
They’re also curious to know whether they still change color when hunting solo, how the changes affect their prey and if other predatory species of fish utilise similar colour changes.
“We already have footage of hunting behavior of sailfish and mahi mahi where we have seen even more pronounced and more variable color change than in the marlin,” Dr. Burns added.
