IT WAS A BLAZING hot morning and the water was as clear as glass. Cameras in hand, we descended slowly towards the coral reef below, inviting in its soft glow under the constant play of sunlight. Only minutes into our cruise, we were joined by a large school of neon fusiliers that was also exploring the reef. The schooling fish swam elegantly and in perfect synchrony, stopping ever so briefly at a cleaning station along the way. Their colours, with those iridescent hues and that gorgeous background of azure blue, made for a perfect picture to capture. It took barely a matter of seconds to adjust the exposure on my camera. But in those fleeting moments, without warning and out of nowhere, a crocodilefish burst onto the scene. In one clean swoop, it swallowed one of the fusiliers whole, scattered the rest of the school in all directions, and left us all rather stunned

A GAME OF HIDE AND SEEK
The crocodilefish, whose presence we had clearly missed before its attack, now looked colourful and intricately shaded in pinks and mustards. How had we not seen it? We got our answer quickly enough. The fish sank swiftly to the bottom and, as we watched in amazement, blended in with the dark pink boulder beneath it. We had just witnessed a startling display of exquisite camouflage.

For marine animals, life in the ocean is not easy. They encounter all the challenges faced by any terrestrial animal in its environment. In addition, oceans are constantly in motion, with temperature and light always changing. Just staying still can be a challenge too. And with so many neighbours on a bustling reef, add to the list of difficulties the fear of being watched by predators each time one ventures out for a meal.

To cope with this “kill or be killed” survival challenge, some animals in the marine realm have turned to the use of camouflage. And for camouflaging carnivores like the crocodilefish, finding food is quite like playing hide and seek – only here, the stakes are rather high. A predator is under constant pressure to bring its “A game”, especially if it wants to keep up with nimble prey that are also constantly getting better at escaping its clutches.

WHEN PREDATORS PLAY WITH LIGHT

In parts of the ocean where sunlight can penetrate, the lives of many plants and animals are largely governed by the dynamic play of light. Light not only determines where animals live and what they eat but also how they are coloured and consequently, who can see them. A camouflaging predator behaves much like a photographer would underwater, constantly evaluating how best it can utilise the presence of sunlight falling on its immediate surroundings. And so, the positions and movements of a hunting predator in camouflage are rarely an accident or coincidental. More often than not, the predator’s every move is carefully calculated before execution, ensuring that it constantly blends in.

THE ART OF BLENDING IN
As it turns out, the crocodilefish we had seen was “background matching” as a form of disguise, using prominent structures in its vicinity to blend in. While being very much present, it remained almost entirely out of sight. To achieve such exceptional results these camouflaging predators need to pay close attention not just to the movement of sunlight but also the brightness, contrasts and patterns of objects they want to resemble.

Sometimes, animals can change the texture and contours of their body and masquerade as other plants and animals. A frogfish often convincingly fools us when it mimics a brightly coloured sponge or urchin. Their plump and irregular shape breaks up their fish-like outline, keeping them hidden in plain view despite their bright colours. As if this weren’t enough, many have a handy-looking “rod and lure” on their forehead. Unsuspecting prey that venture too close to the worm-like lure get swallowed before they even become aware of the presence of their predator.

While some need to seek backgrounds that their bodies can camouflage with, other predators come biologically equipped with a kind of in-built camouflage toolkit. These animals can redistribute, intensify or dilute pigments in their tissues to match their backgrounds in colour, pattern and even textures, regardless of where they move!

Read the rest of this article in 2017 Issue 3  Volume 147 of Asian Diver magazine by subscribing here or check out all of our publications here.

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