The strangest eyes in the animal kingdom, show how vision techniques vary according to need
The formations of the eyes vary among living organisms, and their ability to see objects and colors varies. The horizontal pupils of the eyes give herbivores a panoramic view of their surroundings, which helps them to see incoming predators, and to avoid obstacles during their escape. Meanwhile, nocturnal predators have vertical pupils to maximize night vision.
However, other types of eyes that exist in our wonderful, vast and diverse world see in ways we might not even be able to imagine. Here are some of the strangest eyes in the animal kingdom, reported by Science Alert :
1. Squid
No other animal has nicks like cuttlefish. Their bells are "W" shaped, a trait that helps animals balance the vertically uneven field of light, which is common in the aquatic depths in which they live.
That's just the beginning. Squids have only one type of photoreceptor. However, the strange, broad pupils of cuttlefish and other cephalopods could facilitate an entirely different way of seeing color, using the way light is scattered through a prism into a rainbow, known as chromatic aberration.
The smaller the pupils (pupil) of the eye, the smaller the effect, and thus the wide pupils of cephalopods will be more susceptible to this. Although this may blur images, blurring is color dependent, meaning that it may be a way to see colors for these seemingly color-blind objects.
It is possible that cephalopods see colors that we do not know, and this may also explain how they can coordinate colors with their environment to camouflage. And unlike other cephalopods, a squid's eyes can rotate in a way that allows it to see the world in 3D as well. And in recent days, scientists have found that these rotating eyes lead to stereoscopic vision that gives the squid another advantage in its environment.
2. Bird
Perhaps birds, with their small, piercing eyes, can see much that we cannot see. Compared to cephalopods, which have only one type of photoreceptor, and to the 4 types we have - we humans - birds have 6; 4 cones give four-color vision, and an unusual rod and double cone perceive colorless motion.
In addition, a protein in birds' eyes could allow magnetic fields to be seen. Migratory birds can navigate very well, as a result of their dependence on a class of proteins called 'Cryptochromes' that are sensitive to blue light.
There is a clear possibility that the birds' magnetic reception is due to the effect of the magnetic field on the quantum property of cryptochromes, and there is also a magnetic filter for the blue color, indicating that sensation may be based on vision.
3. Quad-eyes
The four-eyed (Anableps anableps) is a fish native to South America, especially at the edges of rivers from Venezuela to Brazil. This wonderful beast does not actually have 4 eyes, but its eyes do look like that, they have developed an amazing adaptation, the pupil in each eye is divided horizontally into two parts, allowing it to be able to see clearly under and above water.
This unique adaptation allows this type of fish to find food above or below the surface of the water and also gives it additional protection against predators, spending all its life swimming at the surface and needing this extra protection. In this way, the fish can see above and below the water simultaneously to monitor both their prey and their predators.
The proteins in the photoreceptor cells in the retina are also slightly different, they are more sensitive to green light in the dorsal retina and more sensitive to yellow light in the ventral retina, because fish often live in muddy environments, such as mangroves, and this is believed to improve vision in water. turbidity.
4. Mantis shrimp
Among all the eyes in the animal kingdom, the most complex that we know belongs to a marine crustacean of oropods that lives at the bottom and spends its life in burrows among the rocks at the bottom of the sea. cortical, or what is known as plenums of the thyroid.
The mantis shrimp is considered one of the most accurate sighting creatures on Earth, due to its ability to see even highly complex light beams. It has photoreceptors that see all things; Each eye is fixed on a leg, and can be moved independently, and each eye has the ability to perceive depth.
It has the usual color photoreceptors, can see 5 different ultraviolet frequency bands, and, moreover, can see polarized light; Any direction of vibrations of the wave of light propagation, which is the only animal we know that can see circularly polarized light. In fact, we don't know why the mantis shrimp needs such complex visual organs, because it is very difficult for us to visualize what it sees.
5. Chiton
Chitons are marine mollusks of a class of multi-shell chitons, and chitons contain a shell of 8 separate plates or valves. These plates overlap slightly at the front and rear edges, providing protection, while at the same time allowing the chiton to flex, as well as allowing the animal to turn into a ball when moving away from the rocks.
It was believed that the chiton had no eyes or antennae, but the polyplacour chiton had eyes built into its shields and made of metal; More specifically, it is a type of calcium carbonate known as aragonite.
The simple eyes of the chiton, scattered on the surface of its shell along with hundreds of sensory organs, consist of an aragonite lens covered with a cornea, and a kind of retina, and these tiny primitive organs can actually analyze images, to the surprise of scientists.
What we don't know is how this visual information is processed by the brains, but this information can help us better understand some of the paths that evolution took in the past, so understanding it can tell us a lot about how vision evolved on Earth, in all its fascinating complexity.