There are about 150 species of this unique lizard that we call the chameleon. Everything about them is unique, but the most unique is their eyes. According to a proverb, a chameleon has one eye to see into the future and the other to see the past. Read on to know insightful facts about unique chameleon eyes.
1. Their eyes can move independently
Chameleons have a monocular vision. Its eyes can move in all directions regardless of the direction in which the other eye is looking. This allows them to capture the entire environment around them without having to move their head.
2. While capturing a prey, both eyes should be focused on the prey
In order to estimate the distance of its prey is at accurately, both the eyes of the chameleon must be focused on the prey. The precision of the estimated distance by the chameleons is the best among vertebrate animals.
3. Their eyes have a concave lens
The most unique characteristic of the eyes of a chameleon is a negative lens (concave/ diverging lens) instead of a positive lens (convex/ converging lens). Adding to this is their monocular vision. This allows them to have extraordinarily good vision. They can even see small insects that are 5-10 meters away.
4. Their eyesight is unusually good for a reptile
It is a known fact that reptiles do not have a good eye-sight, for example – snakes. It is assumed that the extraordinary eyesight of chameleons is a result of years of evolution.
5. Uniquely attached upper and lower eyelids
The upper and the lower eyelids of this little reptile are attached in such a way that they allow a hole only large enough for the pupil to adjust its focus.
6. Chameleons can see ultraviolet light
They can’t just see it, they love it! They are cold-blooded and love basking in the sun emitting UVA and UVB rays. When exposed to ultraviolet light, chameleons show increased social behavior and are more likely to reproduce. Exposure to sunlight has a positive impact on their pineal gland.
7. Best image enlargement among all vertebrates
While the lens in the chameleon eye is divergent, the cornea of the eye is convergent, which allows maximum light from the focus enters the eye. The divergent lens then forms an enlarged image of the focused area on the retina.
8. Eyes are not as efficient at night
With a concave lens, the chameleons have an excellent narrowly focused vision. They can detect all kinds of shapes and colors during the day. However, their eyesight is not good at night. Human eyes consist of rods and cons.
Rods are used to sense the presence of light, while cons perceive different colors. While chameleons have one extra con than humans do, but they do not have rods. Which is why they see colors more vividly than we do, but cannot see in low light/ darkness the way humans can.
9. Extraordinary eye mobility
The chameleon’s eyes continuously scan the environment with each eye independent of the motion of the other. This allows them to have a 360-degree view of the environment.
10. What happens when chameleon sees different prey from both eyes
Because of the monocular vision of two eyes and only one tongue, one might think that the chameleon will be indecisive of which prey to catch. However, it is able to decide which prey to aim for. Hence, despite being monocular, both the eyes are aware of what the other eye is at.