Owls are very interesting and mysterious birds. They have some capabilities that no one else has and this is what makes them different. From all the owl’s features, perhaps its eyes are most striking. If you are even a little interested in knowing about birds, then you must have noticed one thing that the owl’s eyes are much bigger than a human eye. But have you ever thought, Why Do Owls Have Big Eyes? If you don’t then this article is very helpful for you.
Before going to the answer you should understand how the human eye works. As we observed that we see directly with our eyes, it does not happen at all. There is a complicated process hidden behind it. We see any object only when the light reflecting from it falls in our eyes.
This reflected light first passes through the cornea. It bends the light so we can get proper eye focus. After that, the light passes by an opening named a pupil. Next by lenses made up of proteins. And finally, the light falls on the retina where the inverted image of the object is formed. The cornea and lenses work together to get a correct focal point at the retina.
There are very special cells present in the retina, called photoreceptors, which convert light signals into electrical signals. Afterward, these signals are sent to our brain through the optic nerves. Then our mind reads these signals and turns them into images. The way the human eye functions, in the same way, owl eyes also work.
Why Do Owls Have Big Eyes?
Now you understood the working of an eye. According to the situations, the shape and size of eyes differ, like human eyes are smaller than an owl. Owl has a very big eye, as you have also noticed. The big eyes are very necessary for them to see. These are very large nocturnal that roam at night. Their big eyes help them to see more at night. Thus it is very reasonable to think that their eyes take up a lot of space within their small skull and leave a very little place for the brain.
Most importantly, you have noticed the dark black part (pupil) of the owl’s eyes is comparatively very big than the other animals. This is so that they can see enough at night. We recently discussed that everything is visible to us if and only if when reflected light from an object captured by our eyes. At the same time, the more light enters our eyes, the more clear we can see and vice versa. The owl pupils are very large due to which very little light coming in the night also enters their eyes, hence perhaps owls are able to see at night.
The shape and size of an eye play a key role to develop an image at the retina. Mostly, the shape of an owl’s eye is cylindrical instead of ball-shaped (like humans). There is a perfect distance between the back and front of the eye, which probably allows the lens to be kept at a proper distance from the retina. Not only the size but the perfect position of the eye is necessary for a good view and especially at night. The bigger lens in the eye means more light, so owls will outshine as much light as they can. This is how the bird controls to see even in very dim-light conditions. Resultant, the big eyes provide a superior binocular field of vision.
How Do Owls See At Night
You must have heard from someone or other that owls can be seen even at night, but they have not told the details of why they are able to do so. If nature creates anything, then it also creates favorable conditions, so it can survive. The sight of owls has been made in such a way that they can also see at night. The main reasons behind this are given below
- A large Number of Rods. It is one of the main reasons that the owl has excellent night vision. Owls have a huge number of rods and not many cones. As a result of which they have good night vision but they lose their color vision.
wait! what did you say rod? You too were surprised to hear this, when I first heard it, I was too. Yes, every animal’s eyes have some photoreceptor cells shaped like cones and rods. Rods are nothing but a kind of photoreceptor cell present in the retina.
These cells are very sensitive towards light and help to give us a good vision even in low light. These rods are about 500-1000 times more sensitive light signals than cones. Therefore, as much as the number of rods, the greater is the ability to see at night. Hence, the owls have a great capability to see at night.
- Big eyes. Owls have very big eyes, especially their pupils and lens. More light can be passed through bigger lenses. I have already told you what the owls benefit from having big eyes.
- Mirror Inside The Eye. On the backside of the owl’s eye is a type of mirror known as tapetum lucidum. This mirror is present behind the rods, when the light rays go behind rods, this mirror again reflects it on rods. As a result, the owl gets two chances to catch the beam of light going inside his eye.
You must have seen that the eyes of many animals start shining when there is light in the night, the reason for this is the tapetum lucidum mirror of their eyes. I know, it must be going on in your mind that if it is so useful then why is it not in our eyes?
Although it is very useful, it still has some faults. It makes blurry whatever we see, during which it does not present in the organisms that roam in the daytime.
Binocular Vision. Owls have an extraordinarily binocular vision comparable to other birds. Binocular vision is described as the ability of an animal having two eyes to see a point at the same time with both eyes. Which increases the depth perception of the animal. Like all birds of prey, an owl has its eyes on the front. Due to having eyes on the front, they get a much better binocular vision than the birds with eyes on the side of the head.
Night Vision. Since most of the owls are nocturnal, which means that they are very active at night. They have been designed in such a way that they can see even in the dark of night, for which the density of retinal rods inside their eyes is very high and the size of the eyes is also very large.
Day Vision. You must have heard people saying that owls cannot see during the day. But that is not true, they are also able to see in the daytime. However, their eye pupils are very big as compared to humans and can absorb much light. So, they close their eyes partially or fully during the daytime to prevent bright daylight from entering their eyes.
By the way, they need less daylight because their food (mice and rodents) mainly comes out only at night. If you see them sleeping half or full, it doesn’t mean that they are sleeping but they are in a wide alert and awake state.
Owl Eyes Facts
- Owls are unable to move their eyeballs, as they don’t have eyeballs.
- The number of retinal rods is much higher than retinal cones, due to which they can see better at night.
- Owls have a wide range of binocular eyesight, so they can see an object with both eyes at a time.
- Owls cannot see anything within their range of a few inches.
- They have very good far-vision, especially in low light conditions.
- They have three layers of eyelids to protect their eyes.
- The eyes of the great horned owl are the biggest of all birds in North America.
Do Owls Have Eyeballs
Like humans or other animals, owls don’t have eyeballs. Instead of eyeballs, they have tube-like or cylindrical-like shapes of their eyes. They are not capable of moving their eye sockets as eyeballs can do. Also, they have the advantage that they can rotate their entire head to get a better view of their surroundings. They can twist their necks about 90° upward-and-downward and 265-270° in any direction, even without shaking their shoulders.
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