Having become acquainted with the peculiarities of animal vision, it’s hard not to exclaim: “Where the nature of the invention is fabulous!” However, let’s sort out in order what amazing facts we are talking about.   

The number of visual organs and their location

The scallop has about a hundred eyes along the edge of the shell, with their help the mollusk tracks predators. In a starfish, which is one of those, photosensitive cells are located on the limbs (“rays”), and in many crabs the eyes are arranged on “stalks”. 

Some species of scorpions have up to 12 eyes, and many spiders – eight each , the famous New Zealand Tuatar lizard, which is considered a contemporary of dinosaurs, is called “three-eyed”. Her third eye is in her forehead!  

“External data” and internal device

The giant squid has eyes with a diameter of up to 25 cm, in each of them there are up to 1 billion photoreceptors. The shark is also a big-eyed creature: the diameter of its “eyes” is up to 12.5 cm, and some of the species are also felt by the skull through a special pineal growth.   

The diameter of the eagle eye is 35 mm. The octopus, as already mentioned, the pupil has a square shape and is equipped with 20 million photoreceptors. In the retina of the neck of the neck there are one million per square millimeter, i.e. five times more than in humans.   

The complex structure of the eyes is not necessarily large representatives of the fauna. For example, the bees have about 5.5 thousand tiny lenses in each eye, and the flies have about 3000. But the aquarium Anableps microlepis (“four-eyed fish”) actually has only a couple, but each eye is divided into segments, one of which is intended to be seen in the air, the other in water.  

Curiously, the dolphin’s retina also has a similar dual setting. Penguin flat cornea allows you to see in the water without distortion. Snakes do not have eyelids, and their eyes are constantly closed by a transparent elastic membrane. And the camel’s eye is designed so that not even a small speck gets into it: strong bones along the edges of the eye sockets are protection against mechanical damage and sunlight, and the eyelashes have the ability to weave and automatically close the eye at the moment of danger. 

Visual acuity and visibility

Even those who are considered the closest genetic relatives of man – monkeys – see three times better than him. And not only them, of course. The eagle, for example, also has three times more vigilant vision than the “king of nature.” The falcon is able to make out a target of 10 cm in size from a distance of 1.5 km, and at a high speed it retains the sharpness of the image of objects. The vulture distinguishes small rodents from a distance of up to 5 kilometers, and the Colias butterfly can distinguish image elements of 30 microns, overtaking a person more than three times.    

Have a fly – just imagine! – the rate of change of images is 300 frames per second, that is, it surpasses a similar human ability by 5-6 times. A cockroach notices movement by a value of 0.0002 mm.     

Deep water fish, as you know, can see in pitch darkness, and all because the density of sticks in the retina in them reaches 25 million / sq. Mm, which is 100 times more than in humans. Cats also perfectly see in the dark, because their pupil can expand to 14 millimeters. And dogs in the dark see three times better than we do.

Chameleons and seahorses can watch in two directions at once, this amazing ability they owe to the fact that their eyes move independently of each other. The record holder in panoramic vision is a woodcock bird, in which it is almost circular! In a pigeon, the viewing angle is 340 degrees, in a horse with a raised head, vision also approaches spherical. In dogs, visibility is on average 240–250 degrees, which is 60–70 units higher than the similar capabilities inherent in humans.

The dream of all-seeing has accompanied humanity since ancient times. For example, the Greeks had a stagnant Argus. What about the Buddha? What about Shiva? But the animal kingdom, as we see, is often ahead of this dream …