Hiding in Plain Sight
It’s no mystery that there are numerous camouflaging methods through which prey hide themselves from their predators. Often, when we look hard enough, it can be observed that many of these tactics involve some kind of “blending” into the environment, such a tree frog settled amongst the green algae of a swamp. Even zebras, with their seemingly bold black-and-white stripes are capable of blending in with the shadows of tall grass on the plains with these distinct patterns (in addition to providing a pretty neat cooling method as well). Staying out of the hunter's sight has often proven advantageous for the hunted, but what about tricking the predators who don’t rely solely on vision? Many species don’t just rely on visual camouflage, but rather on masking other sensory giveaways, such a scent. One such species that does so is the vibrantly colored Harlequin Filefish, native to the coral reefs found in the Indo-Pacific Oceans.
The Filefish consumes a highly specific diet of corral local only to its’ own habitat. Similar to the way sulfur compounds found in garlic can leave you smelling much like the pungent plant itself, the Filefish secrets an odor similar to the coral it consumes in its’ diet. In doing so, it cleverly blends into its’ habitat and remains undetected by its’ predators.
This hiding-in-plain-sight tactic is not a perfect science, however. An experiment was conducted where two different groups of Filefish were fed separate diets of two distinct species of coral. When placed in a tank with filled with both predators and one of the species of coral, only the fish in the group whose previous diet matched the coral found in the tank where able to remain undetected. Those belonging to the other group were as easy to seek out as any other undisguised type of prey. Fortunately for the Filefish, it’s bright coloring act as a secondary defence against predators, allowing it to blend in with the coral in its’ environment.
Very little is known about this particular form of chemical camouflage, and there is still much to be discovered. Some evidence, though not confirmed, suggests that the amino acids found in the fish’s mucus membranes responsible for most of their odor matches closely with their diet of coral. The case of the Harlequin Filefish is unique, in that it is the first non-insect species known to use chemicals to disguise its’ odor. Who knows what other interesting tactics organisms are using to avoiding being someone else’s lunch?
Posted by Hilary Mello (2)