Humans have two eyes, which we can use simultaneously for a wider range of vision. Animals, however, are different. While many animals we know and commonly see have two eyes, there are many animals with more than two eyes.
Why do animals need more than two eyes? Certain animals will require extra eyes to help them in their everyday survival. Most animals live in more challenging environments than humans and their eyes help them spot their prey and predators to survive and prevent extinction.
In this article, we’re going to talk about specific animals with more than two eyes and discuss why they need them. You’ll also learn new and interesting things, such as animals that you may not know have more than two eyes, as well as help you better understand the functions of the animal eyes.
Spiders are arachnids under the subphylum Chelicerata. They are the most commonly known creature with more than two eyes. The majority of spider species have a total of eight eyes, although some kinds of spiders can have up to 12.
The spider’s eyes that are closest to its face are used to measure the size, color, and shape of adjacent objects. Eyes that are farther to the sides of their head are used to measure motion. Since spiders are tiny creatures with many predators, they have the benefit of enhanced vision due to their numerous eyes, which helps them survive.
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FACT: Spiders have several eyes that enable them to detect predators, hunt for and catch their prey more effectively, identify potential partners, and distinguish between rivals.
Iguanas are well-known herbivorous lizards that are native to tropical areas such as Mexico, Central America, South America, and the Caribbean. Iguanas have even been kept as pets in many homes.
At first glance, you might notice that they only have two eyes on their head. However, iguanas have three eyes in total. On the top of their heads, Iguanas have what is known as a third eye. The parietal eye, which resembles a pale scale, is used to detect light and motion. This third eye is helpful, particularly in recognizing approaching predators from above.
With three eyes, iguanas have excellent vision and that helps them survive. Their eyes allow them to perceive color, shapes, light, and movement at a great distance, allowing them to effectively hunt for food and evade predators.
Praying mantises are insects that got their name because they hold their enormously long front legs in a stance that resembles prayer. When you see or imagine a picture of a praying mantis, you might assume that they just have those two large eyes on the sides of their head. However, praying mantises possess three additional eyes in the middle of their heads.
A praying mantis has five eyes in total: two large compound eyes that are visible to human eyes and are utilized for depth perception. The other three, smaller eyes are situated in the middle of their heads and are utilized to sense light.
FACT: Praying mantises can turn their heads 180 degrees! With the help of their five eyes, they can effectively scan their surroundings to hunt for prey and avoid predators.
Tuataras are reptiles native to New Zealand. They closely resemble an iguana, which is typically thought of as a large lizard with spikes. Although tuataras closely resemble lizards, they belong to a separate lineage known as the order Rhynchocephalia.
Many of you may not know this but tuataras have a total of three eyes. They have a third eye on top of their head, but it does not have eyesight despite having a retina, lens, cornea, and nerves. As the tuatara grows, however, the third eye becomes covered by scales.
FUN FACT: Tuataras don’t use their third eye for seeing. Instead, they use it to determine the time and season of the year.
The Komodo dragon, often called the Komodo monitor, is a native to the islands of Indonesia and is a member of the Varanidae family of monitor lizards. Many of you might not be aware that the Komodo dragon, the largest lizard in the world, has more than two eyes.
Komodo dragons have three eyes altogether. They have a third eye, known as a parietal eye. It is located on their heads, facing the sky and sensing light and dark. It functions as a natural photoreceptor and a light sensor, determining the time of day, night, and season according to the light it is exposed to.
The Komodo dragon’s three eyes provide it with better vision, allowing it to see far-off objects, generally up to 300 meters away from them. With their third eye, they can find food more successfully and avoid competitors or predators.
Anableps, most commonly known as four-eyed fish, are fish that live in fresh and brackish water that is typically found in South America and Trinidad. Four-eyed fish are also known as:
- Largescale Foureyes
- Stargazer Fish
- Striped Four-Eyed Fish
At first glance, you’ll see two main eyes on the fish’s head but each eye contains two lobes, each of which has a pupil, resulting in distinct vision.
One lobe watches the top of the sea, while the other lobe monitors the depths of the ocean. Anableps have a better chance of surviving and reproducing because they can see both their aerial and aquatic environments at once, which makes it easier for them to find food while avoiding predators.
Bees are winged insects that have over a thousand different species and are most well-known as pollinators. Many people may assume that bees have two eyes on their heads, however, bees are found to have five eyes. There are two huge compound eyes that we normally see on their heads and three smaller ocelli eyes that are positioned in a triangle in the middle of their head.
Bees use the two enormous compound eyes to perceive and see other insects and animals, as well as patterns, shapes, and flowers. Both eyes have numerous small lenses to help them see clearly.
The three tiny ocelli eyes, also known as simple eyes, are used to detect light but not forms, which helps them detect approaching predators if they are above them.
Sea stars, most commonly known as starfish, are invertebrate members of the echinoderm class that are typically found in the ocean and differs in the number of arms, color, structure, and pattern of their bodies.
The five-armed starfish we encounter most frequently would lead you to believe they don’t have eyes at all. However, starfish have eyespots at the end of each arm instead of the head-mounted eyes that most animals have. These eyespots, instead of having a vision, can only distinguish between light and dark.
Starfish with more than five arms will likewise have more eyespots. These eyespots can distinguish between different light levels, allowing them to navigate their surroundings, look for food, and avoid becoming prey for other creatures.
Horseshoe crabs are marine arthropods of the family Limulidae. Although they are named crabs, they are chelicerates, a subphylum that is closely related to arachnids. Since they are not commonly seen on beaches compared to actual crabs, you might think horseshoe crabs don’t have eyes at all. However, horseshoe crabs have a total of 10 eyes. Their 10 eyes are divided into categories:
- Lateral compound eyes
- Lateral simple eyes
- Median simple eyes
- Rudimentary lateral eyes
Their two lateral compound eyes are utilized for partner selection. The lateral and median simple eyes are stimulated at night to significantly boost each light receptor’s sensitivity. This enables the horseshoe crab to recognize other animals in the shadows.
The horseshoe crab also possesses five rudimentary lateral eyes; each of these eyes is capable of detecting ultraviolet radiation from the sun and moonlight. These help them follow the lunar cycle which is important for their spawning period which peaks on the new and full moon.
Scorpions are eight-legged predatory arachnids that can be identified by their pair of grabbing pincers and their narrow, segmented tails with a stinger. You may have seen scorpions outdoors or on television, but did you know that they have 12 eyes?
Scorpions have 12 eyes, with two of them prominently situated on top of their heads and the remaining ten divided on either side of their lateral bodies. These eyes are capable of detecting motion and distinguishing between dark and light. The extra 10 eyes primarily serve as light detectors, detecting brightness variations at ten log units’ lower intensity than the prominent eyes.
FACT: The scorpions’ 12 eyes are useful for locating prey and spotting predators, helping them survive.
Box jellyfish are cnidarian invertebrates identified by their box-like body when viewed from above. Jellyfish have a net of nerves rather than a brain. They have a dense concentration of neurons in their ring nervous system, which serves as a hub for processing sensory and motor activities.
Box jellyfish have 24 fully formed eyes, uniformly distributed on each of their four body sides — six eyes on each side. 20 of the 24 eyes are rudimentary eyes that can discern between light and dark and help with navigation, obstacle avoidance, and light sensitivity.
Its four main eyes include upper and lower lenses that can create images, and resemble the eyes of vertebrates like humans.
You might be familiar with scallops as a common delicacy. The term “scallops” refers to several species of marine bivalve mollusks that belong to the Pectinidae taxonomic family.
There are over 300 different varieties of scallops, and each one has more than a hundred eyes. Along the edge of the mantle lining of their shells, scallops can have up to 200 tiny eyes.
The pupils of these eyes can enlarge or constrict depending on how much light is entering them through a concave mirror.
Their retinas can each discern distinct aspects of their surroundings, helping them look for food and evade predators.
The term “clam” is used to refer to various bivalve mollusk species. Giant clams are well-known for producing pearls and for being a delicacy. As infauna, giant clams spend the majority of their lives partially submerged in the sand of the ocean floor. Giant clams possess 700 eyes which are located on their mantle. These eyes are also known as hyaline organs.
As they expose their mantle, their eyes are used to sense changes in light and motion. Their eyes help them recognize and resist predators.
FACT: The giant clam’s 700 eyes help them detect even slight shifts in light, enabling them to close their shells and stay safe inside them if there is a potential danger.
Chitons are marine mollusks of various sizes that belong to the Polyplacophora class — previously called Amphineura. Chitons are uncommon sea creatures. Nevertheless, many Native Americans enjoy it as a delicacy.
Chitons are marine animals with 1,000 eyes that are situated on their shells. These 1,000 eyes can produce focused images and can see objects that are 6 feet away from them even in the darkness of the ocean floor. Throughout their lives, they can develop new eyes to replace injured ones. As a result, the chitons are better able to see and react to approaching predators, clamping to the substrate beneath them to prevent being dislodged or eaten.
FACT: Because of their 1,000 eyes, chitons can easily locate food and protect themselves from predators, preventing their kind from extinction.
The monarch butterfly is a type of milkweed butterfly in the family Nymphalidae. It is one of the most well-known and extensively researched butterflies on the planet. They are also known for their winter migration when millions of monarch butterflies make their journey from the United States and Canada to southern California and Mexico.
Depending on the region, there are other common names that the monarch butterfly has, including:
- Common tiger
- Black-veined brown
Monarch butterflies have two main eyes that are capable of detecting depth, motion, and images. They are single-chambered and gauge light intensity. The butterflies also have up to 12,000 compound eyes, which are eye lenses that allow them to see many things in numerous directions at once. Despite their small size, they are animals with the most eyes, which considerably helps in their daily survival.
FACT: These 12,000 eyes give monarch butterflies a wider range of vision. A monarch butterfly can see 314 degrees around itself. This helps them in identifying predators and looking for food and water sources.
Our human eyes and brains work to help us see. They enable us to see what is around us and determine an object’s size, shape, color, and texture in a single look. Our eyes help us know if an object is moving toward us and help us estimate how fast it is moving. We use our eyes to keep ourselves safe; if we see a potential hazard, we’re able to steer clear of it. As a result, our daily lives often greatly depend on our vision.
Given how much humans rely on our eyes, animals depend on their eyes even more. Since animals live in different environments and face much more difficult conditions than people do, animals often need more eyes for their daily survival.
Numerous animals must find prey to survive. However, those animals who prey on other animals also have predators of their own. Because of this, certain animals will require more than two eyes to better observe their predators and avoid them.
Many animals are too small and need more than two eyes not only to avoid predators but also to find shelter and food sources. In addition, animals have an instinct to breed and reproduce. Since they live in a diverse habitat, they will need more than two eyes to find mates and avoid rivals.
Numerous animals possess exceptional skills, distinctive features, and individual traits that make them extraordinary. All of the special features that animals have are to help them in their daily survival. In the end, animals need more than two eyes to help them survive. Without their numerous eyes, they would probably all be hunted down to extinction.
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