Among animals capable of changing colors we mean octopuses, cuttlefish, some amphibians and, of course, the chameleon. We most often associate this ability with the need to camouflage ourselves from potential predators. But the art of cross-dressing can have many other functions in animals and not just prey. German scientists from Humboldt University (Berlin) have just shown on the pages of the journal Contemporary Biology that some large animals use this technique to hunt.
Striped marlin can swim at a speed of 120 km/h
And not just any predator, because it’s a striped marlin (Kajikia audax), one of the fastest fish in the world, its aerodynamic body allows it to reach a maximum speed of around 120 km/h. Marlin hunt schools of sardines in groups, each member taking turns plunging down like a missile on its prey.
For the first time, scientists were able to visualize and record with drones the rapid color changes of marlin stripes during attacks. In total, the researchers analyzed 12 videos with a total of 24 attacks by so many marlin on schools of sardines (Sardinops sagax) of the Pacific Ocean. High-resolution images made it possible to quantify the contrast of the animals’ stripes.
It turns out that when a marlin runs into a school of sardines, its stripes become lighter and lighter almost immediately. Before it returns to its original coloration when the hunter moves away after eating some prey.
Turn on the lights so you won’t be disturbed
For the researchers, this strategy, by informing its peers that it is preparing to attack, allows the marlin to be undisturbed by a competitor. The color change simply prevents it from being stepped on, so to speak…
In addition, the videos revealed that the color changes were much smaller when the marlin attacked individual fish, strengthening the scientists’ intuition about their informative role in group hunting of large populations of prey.
In addition to coordinating their attacks, the researchers believe that these changes in the intensity of the stripes could also allow the predators to disrupt schools of sardines in their defensive avoidance strategy, which in turn involves collectively coordinating their escape.
They believe that such color variation must be much more widespread than previously believed in the world of predators.