An investigation carried out by Australian scientists on the eyes of crocodiles confirms that they have a unique look and vision to stalk their prey on the surface of the water . The secret is in the fovea , an area that contains receptors that give you sharper vision. The fovea is the part of the retina that helps us to have a sharper and more detailed vision, and in the case of crocodiles it is shaped like a stripe and not a circular spot as in other animals. That allows these voracious and gigantic reptiles to explore the surroundings without having to move their heads. Furthermore, crocodiles are even capable of sleeping with one eye open if an animal or human is nearby or if they sense danger.
Unlocking the secrets of the crocodile’s vision
The scientists who carried out the study, published in the Journal of Experimental Biology , also found a series of differences in cone cells, responsible for detecting colors, in all crocodiles, both saltwater and freshwater. . Nicolas Nagloo, one of the authors of the research, suggests that although the vision of crocodiles underwater is very blurry, they still use their eyes. And it is that although in the water the light conditions are different in salt and fresh water habitats, crocodiles can adjust their gaze to those conditions. “Generally, the light is bluer in salt water environments and redder in fresh water. Animals know how to adapt to this,” says Nagloo.
Nagloo and his colleagues studied the eyeballs of young specimens of saltwater and freshwater crocodile species. When they measured the light absorbed by photoreceptors in the retina, they found that those in freshwater crocodiles shifted towards redder and longer wavelengths, compared to their saltwater cousins. This difference in vision sensitivity is intriguing, because although these large predators are semi-aquatic, they hunt, eat, and mate on land . “It’s surprising since crocodiles can’t focus well underwater, but their light-sensitive reaction seems to be important to them,” says Nagloo. “That implies that there is potentially some aspect of their underwater behavior that we don’t yet know about.”
Overall, the crocodile’s vision appears 6-7 times less accurate than that of humans, but the linear fovea is perfectly suited to its lifestyle. The fovea is a small depression in the retina that contains a large concentration of receptor cells. It is generally circular in shape and is located in the center of the retina, thus providing animals with a very high surface clarity, in a small area of their visual environment. This small area provides us with high resolution information and allows us, for example, to read; But human beings have to move our eyes and observe in detail to capture and understand a scene.
In the case of crocodiles, vision spreads through the center of the retina, and that gives them maximum clarity along the visual horizon.
This arrangement reflects the predator’s ability to lurk only with its eyes above the water and wait motionless for its prey near the riverbank.
