A lions eyesight is arguably their most important sense. Along with a highly developed sense of smell and incredible hearing, these apex predators have a big advantage over most of their prey. Their eyesight, all though no better than ours during the day is far superior at night, lions are said to be able to see eight times better than us in the dark.
Lions see mainly in blue and greens, with highly developed night vision. This doesn’t mean they can see in the dark, if it where pitch black a lion would be blind as well. The way a lions eye is designed helps them pick up and amplify very faint light such as the that emitted from stars and the moon.
Their eyes are able to enhance this faint light through a number of methods-
Inside the eye-
- There are more rod cells than cone cells in the retina of the eye. These are photoreceptor (light-sensetive) cells, cone cells being colour sensitive and rod cells are light-sensitive. Lions having more light sensitive cells packed tightly in the fovea (most sensitive area of the retina), this means they only need 1/6th of the light that humans need to see in.
- Lions have what is known as a Tapetum lucidum, this is a reflective layer of cells positioned behind the retina. This means that light entering the eye will be absorbed by either the rod or cone cells, light that passes through the retina and the photoreceptor cells is reflected back by the Tapitum lucidum and the light-sensitive cells have a second chance to absorb the light waves, in effect doubling the effectiveness of their night vision. This reflective layer results in the eerie ‘eye shine’ that you see when you shine a light on animals at night. Most animals have this layer to a varying degree, but one animal I have noticed doesn’t have eye shine is the rhino.
Outside the Eye-
- Sounds strange but the outside characteristics of a lions face enhance their night vision. The white strips under their eyes reflect faint light into the eyes, maximizing the amount of light entering the eye. This characteristic is a good indication that this animal is nocturnal, if you look at cheetah eyes the opposite is true. Cheetah have black tear marks reducing the glare, while they are hunting in the daylight hours. Much like the way an American Footballer puts black face paint under their eyes.
To sum up human senses are very different to animals relying mostly on our large brain to get us through life. Our eyesight and our hearing is fairly good while our sense of smell is very weak compared to most animals. Being humans our perception of the world around us is very narrow and it is very hard for us to imagine anything over and above what we can sense and see. For instance many snakes have heat sensitive receptors on their face, giving them a thermal image of their surroundings. Many birds can also see Ultra-Violet light waves, but that is a whole different story.