9 Animals That Have More Than 2 Eyes

 Here are nine animals that have more than two eyes:

1. Horseshoe Crab – Has 10 eyes spread across its body, including on its shell and tail. Horseshoe crabs are fascinating creatures with a unique visual system. Their 10 eyes serve different purposes and are spread across various parts of their body:

1. Two large compound eyes on the sides of their shell help them find mates.
2. Two median eyes on the top of their shell detect ultraviolet light.
3. Two rudimentary lateral eyes near the median eyes assist with light detection.
4. One endoparietal eye located in the center of the body.
5. Two ventral eyes on the underside, helping them navigate the ocean floor.
6. A photoreceptor on the tail (telson) helps them sense light and orientation.

Horseshoe crabs have been around for over 450 million years, making them one of Earth's oldest living species! Their blue blood is also crucial in medical research because it detects bacterial toxins.

2. Jumping Spider – Typically has 8 eyes arranged in rows, providing excellent vision. Jumping spiders (Salticidae) are known for their 8 eyes and incredible vision, which is among the best in the arthropod world. Their eyes are arranged in a way that gives them both sharp focus and a wide field of view:

Eye Arrangement:

1. Four large front-facing eyes (Principal Eyes) – Provide high-resolution vision and depth perception, essential for judging distances when jumping.
2. Two smaller side eyes (Anterior Lateral Eyes) – Help detect motion and provide peripheral vision.
3. Two back eyes (Posterior Median and Posterior Lateral Eyes) – Further expand their field of view, helping detect predators and prey from different angles.

Special Features:

• Jumping spiders can see in color, including ultraviolet (UV) light.
• Their retinas move inside their principal eyes, allowing them to "look around" without moving their head.
• They rely on their exceptional eyesight for hunting instead of webs, stalking and leaping onto their prey with precision.

3. Harvestman (Daddy Longlegs) – Usually has 8 eyes, though some species have fewer. Actually, there's a bit of a mix-up! Harvestmen (Opiliones), also called Daddy Longlegs, typically have only two eyes—not eight—unlike spiders. Their two simple eyes are located on a small raised structure called an ocular tubercle on their head. However, some species in deep caves have no eyes, while a few rare ones have four eyes.

If you were thinking of an eight-eyed arachnid, you might be referring to true spiders, like cellar spiders (Pholcidae), which are sometimes also called "Daddy Longlegs."

4. Box Jellyfish – Has 24 eyes, including some that can detect color. Box jellyfish (class Cubozoa) have an impressive 24-eye visual system, which is far more advanced than most jellyfish. Their eyes are arranged in four sensory structures called rhopalia, located around their bell.

Box Jellyfish Eye Types:

Each rhopalium contains six eyes, making a total of 24 eyes, divided into four types:

1. Two Camera-Type Eyes (One Upper and One Lower) – These function similarly to human eyes, with a lens, retina, and cornea, allowing the jellyfish to see detailed images and even detect color.
2. Two Slit Eyes – Help detect obstacles and movement.
3. Two Pit Eyes – Likely used to sense light and shadows.

Why Do They Need So Many Eyes?

• Despite lacking a brain, box jellyfish can navigate complex environments, such as avoiding obstacles like mangrove roots.
• Their camera-type eyes help them track light and objects in their surroundings.
• Some species even have an advanced sense of up and down, helping them stay oriented in the water.

5. Starfish – Has an eye at the end of each arm, meaning some species have 5 or more eyes. Starfish (sea stars) have a fascinating visual system—each of their arms has a simple eye (ocellus) at the tip, meaning species with five arms have five eyes, while others with more arms can have up to 50! 😲

How Do Starfish Eyes Work?

• Starfish eyes are very simple compared to human eyes; they can detect light, dark, and large shapes, but they don’t see fine details.
• They help the starfish navigate by detecting coral reefs and avoiding open water, which reduces their chances of being eaten.
• These eyes lack lenses, so they can’t focus like our eyes, but they still provide enough vision to guide movement.

Fun Fact:

• Scientists have tested starfish vision by placing them near a reef. They move toward the reef, proving they use vision to find their way home!
• The blue Linckia starfish has some of the most studied starfish eyes.

6. Scorpion – Can have 6 to 12 eyes, depending on the species. Scorpions have 6 to 12 eyes, depending on the species. Their eyes are specialized for detecting movement and navigating in low light.

Scorpion Eye Arrangement:

1. Two large median eyes – Located on the top of the head, these help with basic vision and detecting light levels.
2. Several lateral eyes (2 to 5 pairs) – Located along the sides of their head, these are highly sensitive to movement and help scorpions detect predators and prey in near darkness.

Night Vision Masters:

• Scorpions have exceptional night vision, allowing them to hunt in complete darkness.
• Their eyes are extremely sensitive to ultraviolet (UV) light, which is why they glow blue-green under UV light—a feature that scientists are still trying to fully understand!
• Even in total darkness, scorpions use their hairs and sensory organs to detect vibrations and locate prey.

7. Mantis Shrimp – Has 16 photoreceptor types in its complex eyes, allowing it to see ultraviolet and polarized light. Mantis shrimp have some of the most complex and advanced eyes in the animal kingdom. Their compound eyes contain up to 16 types of photoreceptors, compared to the three that humans have (red, green, and blue).

What Makes Mantis Shrimp Vision Special?

1. 16 Types of Photoreceptors – They can see a huge range of colors, including ultraviolet (UV) and infrared light.
2. Polarized Light Detection – They can see polarized light, which helps them detect hidden prey and communicate with other mantis shrimp.
3. Independent Eye Movement – Each eye moves independently, giving them a wider field of view.
4. Trinocular Vision in Each Eye – Each eye has three different regions that focus on objects separately, allowing for extreme depth perception.

Why Do They Need Such Incredible Vision?

• Helps them detect prey and predators in coral reefs.
• Used for communication—some species have hidden color patterns only visible in UV light.
• Aids in their famous hunting technique, where they strike prey with one of the fastest movements in the animal kingdom (their punch can shatter aquarium glass!).

8. Tuatara – A reptile with a third eye (parietal eye) on its forehead that helps detect light cycles. The tuatara is a unique reptile native to New Zealand, and one of its most fascinating features is its third eye, also called the parietal eye.

What is the Parietal Eye?

• Located on the top of the head, this third eye has a lens, retina, and nerve connections—but it’s not used for detailed vision like the other two eyes.
• It is mostly light-sensitive and helps regulate circadian rhythms (day/night cycles) and seasonal changes.
• In young tuataras, the third eye is more visible, but as they grow, it gets covered by scales and pigment.

Why Do Tuataras Have It?

• It may help detect light intensity changes to adjust their body’s internal clock.
• Some scientists believe it might help sense predators from above or regulate body temperature.

Fun Tuatara Facts:

• They are not lizards! They belong to an ancient reptilian order called Rhynchocephalia, which dates back over 200 million years.
• Tuataras can live over 100 years and have one of the slowest metabolisms of any reptile.
• They are often called "living fossils" because they have changed very little since the time of the dinosaurs.

9. Dragonfly – Has up to 30,000 lenses in its compound eyes, giving it near-360-degree vision. Dragonflies have some of the most advanced eyes in the insect world. Their massive compound eyes contain up to 30,000 tiny lenses (ommatidia), giving them near-360-degree vision and making them incredible hunters.

What Makes Dragonfly Vision So Special?

1. Huge Field of View – Their eyes take up most of their head, allowing them to see almost all around them except for a tiny blind spot behind.
2. 30,000 Individual Lenses – Each ommatidium captures a small part of the scene, creating a detailed mosaic-like image.
3. Color Vision Beyond Humans – Dragonflies can see UV light, polarized light, and more colors than humans, allowing them to track prey with extreme precision.
4. Superfast Motion Detection – They process images at an incredibly fast rate, helping them detect and catch fast-moving prey.

How Does This Help Them Hunt?

• Dragonflies predict where their prey will be, instead of just reacting, making them 95% successful hunters—one of the highest success rates in the animal kingdom.
• Their binocular vision allows them to track moving objects with extreme accuracy.

Fun Fact:

• Some species have split eyes—the upper part detects movement in the sky, while the lower part focuses on the ground.