If you wore glasses as a kid, you probably got teased and called “four-eyes” by your peers. But did you know that some animals actually have four eyes? In fact, some have many more than that! Keep reading for a list of 10 animals with more than two eyes.
What You'll Learn Today
Animals With More Than Two Eyes
1. Iguanas
Iguanas are found in the wild in parts of North and South America. You wouldn’t know it to look at them, but these reptiles actually have three eyes.
Two of these eyes are visible; the third is not. This third eye is located on top of the iguana’s head and is known as a parietal eye.
The parietal eye cannot technically see objects, but it can detect movement and light. It helps the iguana pick up on changes in their environment as well as approaching predators.
2. Tuataras
Tuataras are lizard-like reptiles found only in New Zealand. They are the last remaining member of a reptile family that is older than the dinosaurs.
Like iguanas, tuataras have a third eye on the top of their head. This parietal eye can sometimes be seen on very young tuataras, but it is soon covered by scales that render it invisible.
Interestingly, this third eye is thought to help the tuatara regulate its internal temperature. Unlike other strictly cold-blooded reptiles, tuataras have higher metabolisms, which allows them to produce their own body heat.
3. Komodo Dragons
Native to the Lesser Sunda Islands of Indonesia, the Komodo dragon is the largest lizard in the world. Like iguanas and tuataras, Komodo dragons have an invisible third eye on top of their heads.
This parietal eye can sense light and temperature changes, so it helps the Komodo dragon determine seasons and times of day.
The eye is sightless and covered in scales.
4. Fish
Several kinds of fish have more than one eye.
The starfish, found in various regions of the world’s oceans, typically have an eye at the end of each leg. Some starfish have five legs, while others have more; so the number of eyes they have will vary depending on their number of legs.
Box jellyfish, which are located in various tropical regions of the oceans, have 24 eyes, six on each side of their bodies. Only four of these eyes can see objects; the others are rudimentary eyes, which are sensitive only to light changes.
The four-eyed fish of South and Central America technically have just two eyes, but each eye is divided into two parts, and each part has its own pupil. Thus, they can see in four directions at once, effectively giving them four eyes.
The lamprey is an ugly-looking blood-sucker found in many coastal regions that has four eyes. The top two are light-sensitive, while the bottom two pick up on movement; working together, these four eyes allow the lamprey to hunt for prey in a variety of water and light conditions.
5. Mollusks
Most mollusks have more than two eyes. Those belonging to the group known as scallops have between 100 and 200 eyes, while those in chiton genus have around 1,000.
Mollusks are found throughout the world in a variety of marine environments. Their many eyes tend to run in rows along the outer edges of their shells.
Their eyes are tiny, but they can see well. Their pupils enlarge and constrict to account for changes in lighting, and their retinas create clear images of their surroundings.
One type of mollusk, the giant clam, has 700 eyes. These eyes are highly sensitive to light and motion, so even minute changes may cause them to close up inside their shells to protect themselves from danger.
6. Horseshoe Crab
Horseshoe crabs are found in many coastal regions throughout the world. They have ten eyes altogether.
Despite this large number of eyes, horseshoe crabs can’t see very well. One eye detects light, while the rest, which are smaller, can sense movement.
Interestingly, horseshoe crabs can change their eye color to account for different environmental conditions. Their eyes are red when they bury themselves in the sand and blue after they emerge from the sand.
7. Triops
Triops refers to a genus of crustaceans that can be found in warm regions of all continents except Antarctica. These small creatures are often kept as pets.
They have three eyes altogether: two that are visible and one that is not. All three of these eyes are located on top of the head.
The third eye is light-sensitive only and can help the Triops to pick up on light changes in their environment.
Check out this video to learn more about Triops, which are sometimes called tadpole shrimp:
8. Scorpions
Scorpions come in many shapes and sizes and can be found in many parts of the world. These eight-legged creatures also have at least eight eyes–and some have 12.
Scorpions’ eyes are typically arranged in rows along the top of their head. Most have two rows of four eyes, but some have a third row.
Despite all their eyes, scorpions can’t see well. Their eyes are primarily used to sense movement and help them pick up on light changes; they are unable to form clear images.
9. Spiders
Like scorpions, spiders typically have eight eyes. Some have as many as 12, while others only have six.
Unlike scorpions, however, most spiders have excellent vision.
They are highly sensitive to light and movement, and their eyes create images of the objects they are looking at. Their many eyes allow them to get a great view of their surroundings.
10. Insects
Many different kinds of insects have more than two eyes.
Praying mantises have two large eyes on either side of their head, supplemented by three small eyes on top of the head. These eyes do not aid their vision but allow them to pick up on changes in light.
Similarly, bees and wasps also have five eyes, including three light-only eyes on the top of the head. These eyes help them to detect approaching predators.
Dragonflies have two large compound eyes that give them excellent vision and three simple eyes that help them sense light.
Even some species of butterflies have more than two eyes.
Many other insects technically have just two eyes, but these compound eyes are divided into many smaller parts which give these insects the relative vision of hundreds, if not thousands, of eyes. Flies are a good example of insects with this type of compound eye.
Conclusion
As you can see, there are many animals in the world that have more than two eyes. Some of these animals include iguanas, tuataras, scorpions, mollusks, and various species of fish and insects.
