They hunt at night and stay safe from predators because of their ability to see in the dark. In fact, for these animals which are also called nocturnal animals, their vision is better at night as compared to the day. What is different in the eyes of these nocturnal animals that we lack in ours?
As mentioned earlier, not only do these animals have bigger eyes than humans, their pupils also tend to open wider than ours which help in letting in more light. For example, the eyes of an owl are so big that they occupy more than half the volume of its skull. It can see so well in the dark that it can probably sense a mouse anywhere on a football ground in the light of a single candle. Many such animals have a layer behind their retinas, which is called a tapetum.
The tapetum reflects the light coming through the retina once again onto the retina, just like a mirror. This gives the retinal cells a second chance to sense the same image. This tapetum also makes their eyes glow in the dark. Thirdly its eyes have red coloured material chemically a protein which makes its eyes more sensitive to light.
Fourthly the pupiles of its eyes can dilate more thus allowing even the smallest amount of light to enter into the eyes. Because of these four factors the owl can see more clearly in darkness.
Due to the extreme sensitivity of their eyes to light objects appear too bright and uncomfortable to the eyes in the bright light of the day. Surprising enough an owl can rotate its head by ie it can see at the back of his head. In general, their eyes are like ours. Here's how they work. Light comes into the pupil of the eye and is picked up by receptors at the back of the eye. Some complicated things happen, and then nerves carry information about the light to our brains.
The brain makes sense of the information and we see an image. Let's go back to those receptors. There are two major kinds and we have both. Rods only let us see black and white, but they work really well even if the light is very dim. Cones let us see color, but only work well when it's pretty light.
Electromagnetic light energy is everywhere, but very little of it can actually be seen by the human eye. The common bluebottle Graphium sarpedon luctatius has uncommon eyes.
Discover how their vision equips them for survival. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Twitter Facebook Pinterest Google Classroom. Instead, their eyes are shaped like tubes, held rigid ly in place by bone s called sclerotic ring s.
Human eye socket s, which hold spherical eyes, do not have sclerotic rings. Owl eyes are huge! Eyes account for about. There is one drawback to their large eyes.
Owls are very farsighted. Instead, sensitive whisker-like bristles around their beaks help owls detect objects at close range. Owls have terrific binocular vision compared to other birds. Binocular vision describes the ability of animals with two eyes to see an object with both eyes at the same time, giving an animal increased depth perception.
This allows them to have a much greater range of binocular vision than animals with eyes situated on the sides of their heads.
Most owls are nocturnal , meaning they are most active at night. Two adaptations help owls see well in the dark.
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