Octopuses are equipped with a very powerful sensing system in addition to their sharp vision. For example, an octopus whose vision is obstructed can sense the size of objects and the distance between them. Regulation and synchronization of vision is realized with internal and external movement of the lens contrary to human beings. When it faces a threat, the octopus releases dark blue-black ink and tries to repel its enemy. Immediately after the spray, its color changes and it carefully leaves that spot. The secretion glands found in the inner face of the bladder have been programmed to secrete ink the moment the animal becomes frightened. Another function of the ink is to blunt the attacking animal's sense of smell. Even if the animal touches the octopus at this time, it cannot recognize it.
Another striking and important ability given to the octopus is its ability to camouflage. In some situations it tries to protect itself from danger by hiding itself with this capability. If it has not been able to find a suitable place to hide, the octopus swims among the corals and, taking on the color and shape of its surroundings with the help of color cells comprised of richly colored matter (chromatophores) found under the skin, it camouflages itself perfectly.
At first glance the suckers of an octopus are no different from suction cups vacuum pressed onto smooth surfaces. However, in reality this organ is more complex than it appears to be. This organ was not created just for the purpose of sticking on objects. By means of muscles unique to it, the octopus is able to make various maneuvers.
There are approximately 200-250 suckers in two lines on each arm of the octopus. This means there are approximately 2 thousand suckers on its eight arms. There are two small chambers on each sucker. The external chamber is called a cone and the internal one is called a pot. When it sights its prey, the muscles of the external cone take the shape of the surface of the prey and completely cover it. The muscles of the internal pot structure are full of water and, disconnected from the outside world, decrease the inner pressure. This difference from the outside pressure has the effect of a vacuum. The external muscle structure enables the octopus to turn from an erect or parallel angle by decreasing the pressure difference around the object and without destroying the functional structure of the sucker.
In addition to possessing the complex muscle structures explained above, the suckers have an amazing nerve system. The chemical receptors found on the edge of the suckers (chemo-receptors) give feedback regarding the taste of the object, and the pressure and position receptors give information regarding pressure and touch. The nerves of these receptors, gathered in a node, act as a tiny brain. The chain structure extending the length of the octopus' arm connects the suckers and nodes and synchronizes them. This structure enables the animal to lift and raise its arms without need of a command from the main brain. How this amazing task is accomplished by the brain, arm and suckers is a subject that needs investigation.
Only considering its suckers, the octopus appears before us as a creature adorned with perfect artistry and special capabilities. The characteristics of these animals being in a wise and most appropriate form is one of the clearest proofs of the blessings and benefaction of a compassionate and merciful Creator.
Canoglu is a freelance writer from Turkey with a degree on zoology.