Biologists that study animal colouration have the formidable task of demonstrating how animals’ colouration works. The drab lizard camouflages to its grassy surroundings. The iridescent poison dart frog advertises its unpalatability. And stripey zebras disorientates predators as they strike.
It is easy to say that, just because an animal looks camouflaged to its environment, it IS camouflaged. For those that are curious, this isn’t sufficient!? One must first rule out possible alternative explanations. For instance, could the dark colour of the lizard help regulate temperature instead of contributing to concealment, is the bright colours of the poison dart frog cryptic to the eyes of its predators, and is it even possible for a colouration to disorient a pouncing predator.
A classic example of miss classifying an animals coloration was made by the father of animal camouflage, Abbott Thayer. Thayer suggested the–now comical–idea that flamingos are camouflaged: “These various sketches of Flamingoes … show how wonderfully such birds match or reproduce the colors of morning or evening skies to the eyes of the inhabitants of the water… Commonly, the bird’s upper outline ‘melts’ into the sky, leaving the rest of his contour, seen through the water, agitated and muddied by this feet, to be lost in the indeterminate color-mass of the flock.”
This just-so stories of animal camouflage is a warning; to claim an animals colorations functions as camouflage, one needs to test that camouflage’s function.
This Rule 101 of classifying animal colouration persists, not just for diagnosing camouflage, but also for specifying the specific camouflage. To distinguish between whether a camouflage pattern provides reduced detectability (background matching) or impairs recognition (disruptive coloration).