MARLINS CHANGING COLOUR TO COORDINATE CLEVER ATTACKS WITH THEIR GROUPS

Dangerous animals like the killer whale and the white shark may come to mind when we think of ocean predators. However, did you know that one of the sea's most feared creatures is the striped marlin? They are among the fastest animals on the earth, but they also have a special quality that makes hunting in groups well-organised and efficient.

Although colour changes in striped marlins (Kajikia audax) are common, biologists and filmmakers have observed an unusual occurrence. In other words, their stripes get brighter before an attack and go back to normal afterwards.

Researchers discovered that marlins may quickly change colour to coordinate their attacks and prevent injury to one another after examining the contrast of the stripes on more than two dozen attack videos.

“We documented for the first time rapid colour change in a group-hunting predator, the striped marlin, as groups of marlin hunted schools of sardines,” said Alicia Burns, Biologist at Humboldt University Berlin Germany in a statement. “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' colouration after its attack ended.”

Fisherman Christiaan Pretorius saw this feature as well while visiting Baja California, Mexico. His drone footage, which resembles an aerial video taken by Burns and her fellow researchers, depicts a group attacking a school of sardines alternately. "The trade-off between access to prey and possible harm means that, given the marlin's competition for a shared resource, we might anticipate variations in colour-change intensity depending on the level of competition," the researchers writes.