Sometimes the best offense is a good defense.
Pygmy Whales eject a cloud of their own feces to ward of foes and turkey vultures vomit up the rotting carcasses of their latest meals as peace offerings. Ok, but what if you’re fighting against something which is faster, stronger and more vertebrate than you? Then your only hope is to make yourself scarce as fast as you can, preferably holding on to your lunch at both ends. Such is the life of the cephalopod.
Living under the ocean is a full-time test of survival. Since the Earth’s surface is approximately 71% water, there is considerably more predatory speciation below the surface than above. As such, the animal food chain is much more robust. Which means that if there is one creature big enough to eat you, there’s another big enough to eat the both of you. In order to cope with this increasingly bleak outlook, cephalopods have mastered the art of disguise to such a fine degree that it puts the Metal Gear Solid franchise to shame.
The cephalopods which have developed these techniques for concealment typically travel within the mesopelagic zone, which is also known as the “twilight zone”. The predators in the mesopelagic zone, in order to cope with the lack of ambient light, have developed strange adaptations such as bioluminescent “light organs” on top of their heads, which allow them to see their prey in complete darkness.
This creates a problem for many of the highly edible life forms roaming the darkening abyss, which includes pretty much every mollusk. Luckily, evolution has done it’s work and these creatures have developed some pretty unique survival mechanisms. In order to avoid the early stages of digestion, certain cephalopods such as Japetella heathi and the street artist Onychoteuthis banksii, an octopus and a squid respectively, have developed a form of active camouflage, which alters their skin pigmentation thus rendering themselves completely imperceptible to prey.
It’s a cool trick. How it works, is that while living in the shallower and brighter reaches of their environment the cephalopods maintain a translucent state matching the ambient light above. This protects them from creatures swimming below. However, at greater depths, when exposed to the bioluminescent interrogation bulb protruding from their would-be assailants forehead, they are able to, through a rapid chromatophore reaction, alter their skin pigment to match the surrounding darkness, turning them invisible. Researchers found that Cephalopods, such as these reflect twice as much light when they are in a translucent state. So, the only catch is, while in their pigmented state, they leave themselves completely open to predators from below.
Despite the Doctor Strange/Sue Storm look being incredibly effective when you’re bathed in natural light in the upper reaches of the mesopelagic zone, another defensive technique, deployed by certain cephalopods, is the ability to hide in plain sight. Certain octopi are able to take this chromatophore reaction a step further, adjusting their pigment and altering skin texture to resemble objects around them by sight. They are so effective at this it is nearly impossible to spot them with the naked eye when they have assimilated with a plant or object. What’s particularly remarkable is that cephalopods are color blind, yet they are able to accurately reproduce the color palette of the object the are camouflaging, giving them the full seal team six effect, as can be seen in this video.
With Halloween coming up, rather than dress up as sexy Frodo or sexy The Invisible Man again, maybe it’s time to grow out some dreads, throw on those camo shorts you always wear anyway and show a little appreciation for the true masters of disguise, the cephalopod.
SOURCES:
http://www.britannica.com/blogs/2011/11/cephalopod-camouflage-ultimate-invisibility-cloak/
http://www.cell.com/current-biology/abstract/S0960-9822%2811%2901138-9
