The eyes of the seppia (Sepia Officinalis) have one pupil horizontal crack with one “W” form in conditions of full light, while it becomes big and circular when they are in the dark in the absence of light. The common cuttlefish is a cephalopode with a wide and slightly flattened body, characterized by the typical limestone internal shell, the so -called cuttlefish bone. These animals, with 8 arms and 2 tentacles suitable for the capture of the prey, populate muddy and sandy seabed of the Mediterranean, the eastern Atlantic, the Baltic Sea and the North Sea up to 200 meters deep.
As for goats, crocodiles and human beings, even in cuttlefish the form of the pupil reflects evolutionary needs dictated by the niche ecology and the habitat in which they live. First of all, the cuttlefish through the 2 eyes positioned on the sides of the head with iris, crystalline, retina, are mainly entrusted to contrast visual rather than the recognition of color, an effective adaptation in theirs dark underwater environment. In addition, these animals are able to adapt and Change the appearance of the pupil depending on the conditions of the environment that surrounds them.
- In conditions of strong lightingthe pupil has a horizontal crack curve with two vertical cracks on the sides similar to one W.
- In conditions of poor lightingthe pupil becomes big and circular.
The form shape of the pupil represents an evolutionary adaptation useful for different functions. First of all, it is believed that it helps to manage the vertical dysomogeneity of light in theaquatic environmentimproving the visual contrast. Secondly, it provides uniform attention of light along the horizontal line of the visual field, keeping a good vision also in peripheral areasessential for theorientation el ‘identification of predators or prey. On the contrary, it is assumed that the pupil takes on one circular in low light conditions for distribute the light in a more uniform way On the retina, compensating the variations of light intensity between the upper and lower part of the environment in which the cuttlefish lives.
