Masters of Deceit

It’s a still, hot afternoon, no breeze blowing. The jungle is thick and muggy, rich from the abundant gift of rainfall. Near a stream, 100 yards away, is a clearing where the water bubbles down from the surrounding mountaintops. Mist, like the water’s breath, is visible in the shafts of light filtering through the canopy. There’s a shadowy disturbance—a slight movement as a soldier carefully enters the clearing.  He meticulously scans his surroundings, then leans his weapon against a banana tree and squats over the stream.  He’s filling multiple canteens strung together with a cord.  The sniper, concealed by a heavy thatch of vegetation and camouflage paint, scans his field of fire looking for signs of others. They are alone.  A flash suppressor silently noses out of the undergrowth, followed by a rifle barrel.  Peering through the scope, the shooter takes a half-breath and steadies himself. A pulse pecks in his neck.  The target freezes momentarily—as if he can feel the crosshairs on his back.  A muffled “pop”—a single shot, and it’s over.

The professor flicks off the projector and brings up the lights; he turns to face his students and pauses for effect to punctuate the shocked silence in the room. For a university introductory biology class, this is a distinctly unconventional lecture. Today’s topic is ‘Texas Wildlife—Masters of Deceit.’ In that tiered lecture hall, on this listless Friday afternoon, the only sound is the muted hum of air-conditioning. The instructor continues:

“Animals kill for only two reasons: meat and self-defense.  Only man harbors other motives. The struggle between prey and predator is ageless. Have any of you have ever been deer hunting? Raise your hands if you employ the principles of camouflage when you go out. Everything man knows about camouflage was learned from the natural world. And it wasn’t instinctual, it had to be learned.  It was common practice for armies to outfit themselves in bright, gaudy uniforms just two centuries ago.  In today’s world, if you’re going to successfully hunt anything—even your own species—you must be expert at masquerading as something you’re not.”

We’ll leave our wide-eyed freshmen for a while. We’ll be back later, but for now let’s have our own discussion.

We all pretty much know what camouflage is and how it works, but the creative array of applications in the animal kingdom is remarkable. Color matching is probably the most basic. As examples, katydids and green grasshoppers match the color of blades of grass.  Deer hunters know that not only are deer colored to match the Texas landscape but those colors change with the seasons, becoming darker in the fall and winter months.

Disruptive camouflage uses many different colors or natural add-ons to break up outlines. Toads use greens and browns to help them blend with mossy, muddy backgrounds.  Sea turtle shell patterns and colors look like sunlight reflecting on the ocean floor.  And who can top the spots and stripes of a fawn in spring?  Down around the coast, animals use what’s available in the environment to self-decorate.  Take, for example, sea urchins gathering rocks and shells around them or algae growing on turtle shells—anything to change their apparent shape.

One of the most persuasive examples of camouflage is Memesis.  It’s camouflage designed to mimic something else and persuade predators to think twice before attacking.  Actually, it works two ways.  Consider this:  the coral snake uses his bright colors as a warning to all who see him—beware my deadly venom!  Scarlet snakes, a harmless non-venomous species, have similar markings as the coral snake.  They, of course, are trying to convince potential enemies that they are coral snakes. Then too, there are caterpillars that look convincingly like part of an evergreen tree, butterflies that take on the look of a dead leaf and bees that look threatening but actually don’t sting.  Anything to convince harm to pass them by.

Another method involves countershading. This one is a favorite of predators. It’s when the top of an animal’s body is darker than its bottom.  Numerous birds use countershading.  When seen from above, they blend in with the darker landscape below.  This makes it difficult for ground level hunters and other overhead threats to see them.  When airborne and seen from below, they blend in with the lighter sky overhead.  This helps them hunt because prey species below may not see them until it’s too late. Many game fish also use countershading . . . for that matter, so do fighter planes and battleships. 

What if an animal could change its appearance right before your eyes? That’s called active camouflage.  Remember those little green lizards you commonly see here in Texas in your backyard?  You know, the ones with the tiny red flaps of skin under their chins doing push-ups on your porch railing? The push-up routine and flashing of the red dew lap are the testosterone-fueled antics of a male green anole looking to intimidate an intruder or impress a female.  Anoles are often mistakenly referred to as chameleons because they can change skin color from green to brown and back again. Actually, they aren’t true chameleons at all. Turns out they aren’t so much willfully “deciding” to change color as they are reacting to changes in ambient temperature.  Still, it’s a cool enough trick to make them marketable as “pets” at opportunistic pet stores, state fairs and carnivals.

But to understand true active camouflage—dynamic processes so unique, so impressive—we are compelled to rejoin our biology teacher, now in progress.  He’s lecturing on cephalopods (octopus, squid and cuttlefish):

“Did you know cephalopods own the patent on Harry Potter’s invisibility cloak? While cuttlefish are not native to Texas, Octopus and squid are two Texas marine natives that are masters at disappearing before our very eyes—just like the boy wizard. Nothing in the animal kingdom does camouflage better.”

The professor scans his classroom, measuring the effectiveness of his metaphor.

“Visualize an arctic fox in Texas . . . it would never happen; that camouflage is geographically specific. He would stand out like a sore thumb. But a cephalopod can adapt to whatever his surroundings might be—not only in color but also in texture.  He can alter his skin surface into different 3-dimensional patterns depending on his background.  Understand, this background matching is not just good—it’s flawless; and it happens in just over 2 seconds!

Color changes are done through direct neural control of chromatophore organs. These are tiny cytoelastic sacs of pigment with radial muscles attached around the periphery.  Each muscle is controlled by motoneurons that originate in the lower motor centers of the brain and they travel without any synapse to each chromatophore organ.  Here’s what makes this process even more remarkable:  we have demonstrated in controlled experiments that cephalopods are actually color blind!  Put a marker down by this last one—you’ll likely see it again on a test.”

The professor removes his moon-shaped reading glasses and looks up.

“Okay, y’all get that down? Good, ‘cause there’s more than just color matching involved here.  Textural change comes about using changeable skin papillae, also under fine motor control.  This means the octopus, for example, can not only take on the colors of a mottled rock but also make his skin surface bumpy—just like a real rock.  We know this papillae expression is regulated by visual input but we don’t really understand the biomechanics of how the papillae operate as a muscular hydrostat in the skin.

Reflecting on our opening video clip, once again, mankind is taking his camouflage ques from nature. Engineers at Cornell University, for example, have invented ‘stretchable surfaces with programmable 3-D texture morphing’—a type of synthetic camouflaging skin. There are many possibilities. This could, for example, have applications in any situation where there is a need to manipulate the temperature of a material. At M.I.T., engineers are working on military applications for dynamic camouflage which would allow soldiers and military vehicles to adapt to their surroundings instantly. This has implications far beyond basic warfare and could change the nature of camouflage for the next 200 years. As scientists find success with these various projects, I want you to remember one thing for sure:  they’ll have cephalopods to thank for it.”

Our biology instructor takes a step back, closes his folder and summarizes the lecture:

“Being part of nature, it only makes sense for man to look there for solutions to his own needs. Nature is the basic rhythm at our core; the energy that drives the dance of life . . . and death. In the great book of life, predator/prey interactions abound on planet earth.  Whether it be land or water, large animals or small, there is no behavioral ruse more common or important to survival than camouflage.”

He is rudely interrupted by the bell.

“Okay, well, hell . . . it’s Miller time; everyone have a good weekend.”

My sentiments exactly!

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