"Hawk's eyes" is actually not terrible, is it true or a lie?

Appeared in the manga "One Piece"Hawk eyeMihawk "is a character with a superhuman strength, a site that appears in anime" Ghost in the Shell "Hawk eye"Is a high-performance eyepiece that supports sniper links with artificial satellites. Liza appearing in "FULLMETAL ALCHEMIST"HawkeyeIs also portrayed as a superior sniper, and when looking for something that is not a hawk, it depicts a system of fear that monitors humans from all kinds of terminals "Eagle Eye"It seems to me that something" bird's eyes "is such awfully something.

However, looking at actual cases, birds are often reported to hit an obstacle while flying and die. I decided to look at the mechanism of the bird's eyes is really good.

Bird Eyesight Not So Keen After All - Animal News: Animal Planet

"Visual acceptance mechanism of birds" SOBIM: Vol. 31 (2007), No. 3 pp. 143 - 149

◆ Can you distinguish colors?
Professor Shokue Sugita of Utsunomiya University Faculty of Agriculture pointed out that birds are highly discriminating colors, for example, that there are many items with abundant colors and patterns of feathers such as kingfishers, oshidori and peacock in birds To do.


For example, chickens have one kind of visual substances that absorb light as compared to humans. Human beings constitute color vision with three primary colors of red, blue and yellow light, but birds seem to be considered to constitute color vision with four light primaries. However, what kind of color it sees as a bird will not come out of the imagination.

◆ Breadth of vision
The range that you can see without moving the eyeball is called "field of view", but the field of view of birds is generally wide. A pigeon with an eyeball on the side of the head is 169 degrees in view of one eye. In both eyes the field of view that can be covered is 316 degrees. furtherYamashitiThe bird called 359 degrees of view with both eyes. By the way, a human being is about 200 degrees with both eyes.

On the other hand, the range in which you can see the object at the same time in both eyes at the same time can be captured three-dimensionally is extremely narrow, 22 degrees for pigeons and 4.5 degrees for Yamagishigi against 120 degrees for humans. When the pigeon walks, the body moves with the neck fixed, this is thought to stabilize the position of the eyeball and move while focusing on the object.

◆ Bird's eye is about the same size as the brain
The eyeball of a bird has about the same size as the brain or more. The image below is a chicken's brain and eyeball. You can see that the eye ball is much bigger.

Ostrich has the largest eyeball among terrestrial animals, and it can be seen over a distance of 3.5 km.

◆ A mechanism to capture objects far away, nearby objects, freely
The basic structure of bird eyeballs is the same as that of mammals such as humans, but they have their own functions. For example, a lens that plays a role of a lens in the eyeball is softer than a mammal. The bird deforms this soft crystalline lens by a mechanism that does not exist in humans, such as "Mr. Clampton" and "Mr. Bruleuk", and by allowing the lens to protrude when looking at nearby objects, free adjustment of the focal point I can do it.

In the case of mammals including humans, only the lens has the function of adjusting the focus and forming an image, but the bird can change the curvature of the cornea, let the cornea also have a lens function It is. Having a flexible crystalline lens and a cornea in this way makes it possible to adjust the lens more sophisticatedly so that it is possible to freely grasp visually whether it is a distant object or a nearby object.

◆ Why do you hit an obstacle
In the past as GIGAZINE as an article"Why do birds hit obstacles in front of us?"Was posted.

Professor Graham Martin of the University of Birmingham said, "When birds fly down the sky, heads down to see under the eyes, use both eyes to see its direction, or use only one side of the field of view Although these actions are derived from seeds, they will temporarily not be looking at the direction of travel anyway, "he says.

Although it is a bird with a wide field of view and high focus adjustment ability, he is looking downward during flight and often does not see the direction of travel and he sometimes crashes into a structure such as a skyscraper about. Bird's vision is excellent for capturing moving substances, but it seems that it is not suitable for reading the detailed situation of the space.

When returning to the characters who came out at the beginning, their skills are "Cormorant eyes Falcon eyesIt comes from. This is how you are trying to find something enthusiastically, as if a cormorant and a hawk were seeking prey. In other words, rather than being used in the sense that "good eyes" and "ability of visual relationships is meaningful", the meaning of "hunting prey like a hawk" is strong.

in Creature, Posted by darkhorse_log