Have you ever wondered if there are animals that have more than two eyes? While most animals possess only a pair of eyes, some fascinating creatures actually have three, four, or even more! In this comprehensive guide, we’ll explore the incredible world of multi-eyed animals.
If you’re short on time, here’s a quick answer to your question: Some insects, spiders, and crustaceans have multiple eyes which give them a wider field of vision and help them detect predators and prey.
Insects with Multiple Eyes
Flies and Mosquitos
Flies and mosquitos have compound eyes made up of thousands of tiny lenses, allowing them to see in almost all directions at once. Their numerous lenses give them a mosaic view of the world that is great for detecting motion, helping them quickly evade threats (1).
Though their vision is blurry, the many lenses provide keen peripheral vision to keep an eye out for food, mates, hosts, or danger from all angles. Pretty handy when you want to sneak up on someone and slurp their blood!
Research shows that the average housefly has around 4,000 lenses in each eye (2).
Butterflies and Moths
Butterflies and moths also have compound eyes, but theirs are a bit different, with each lens shaped like a long hexagon to reduce glare and help see polarized light. This enhanced vision allows them to perceive color wavelengths unseen by other insects, crucial for finding flowers’ nectar guides that lead the way to tasty treats (3).
Each eye can contain over 17,000 individual lenses, providing a mosaic view of their surroundings. Plus, butterflies have excellent motion detection to keep safe from predators. Moths’ eyes are larger to absorb more light for navigation at night.
Their vision amazes scientists – one study found moths could smell floral scents from an incredible 11 miles away at sea (4)! 🤯
Bees, Wasps, and Ants
Like flies and butterflies, bees, wasps, and ants have compound eyes for detecting fast movement and seeing all around them. Bees have around 6,300 lenses per eye for finding flowers and their way back to the hive (5).
Scientists found special light receptor cells give bees even better color vision than humans! This super sight helps them identify the tastiest blooms. Meanwhile, ants and wasps tend to have fewer but larger lenses, as they navigate more by scent and don’t rely as much on vision.
Ant eyes act like solar panels to warm their bodies! Their lenses also filter out UV light, letting them see special patterns on flowers that guide them to nectar (6). Pretty crafty, aren’t they? 😉
| Insect Type | # of lenses per eye (average) |
| Housefly | 4,000 |
| Butterfly | 17,000 |
| Honeybee | 6,300 |
As we’ve seen, insects have evolved a diversity of compound eyes specialized for their lifestyles and survival needs. Their many-faceted vision never ceases to amaze!
References:
(1) https://askentomologists.com/2015/07/29/do-flies-have-a-blind-spot/
(2) https://www.bbcearth.com/news/meet-the-fly-with-4000-eyes
(3) https://www.sciencefriday.com/educational-resources/butterfly-vision/
(4) https://www.smithsonianmag.com/smart-news/moths-can-smell-flowers-11-miles-away-180970074/
(5) https://askabiologist.asu.edu/bee-eyes
Spiders with Multiple Eyes
Jumping Spiders
Jumping spiders are remarkable for having some of the best vision among spiders, with their large front-facing eyes giving them excellent depth perception. In total, jumping spiders have four pairs of eyes, with one large pair at the front and three smaller pairs on the sides and back of their heads.
The large, prominent pair can move independently, allowing jumping spiders to scan their surroundings and accurately judge distances. According to research, their front-facing eyes have exceptional resolution, allowing them to see details as small as 0.04 degrees.
With this visual acuity combined with sharp focus, jumping spiders can spot, track, and accurately pounce on their prey.
Wolf Spiders
As active hunters, wolf spiders also rely heavily on their vision to catch prey. They have four pairs of small eyes arranged in three rows, providing them with all-around vision while still retaining some ability to detect movement and judge depth.
Wolf spiders’ eye arrangement gives them a very wide field of view, covering almost 360 degrees. Their front-facing middle row of eyes has the best clarity, while the peripheral rows above and below provide motion detection and dim light vision.
According to some estimates, wolf spiders have better low light vision than cats.
This exceptional vision powers wolf spiders’ characteristic hunting behavior – actively pursuing and pouncing up to a foot to catch prey day or night.
Orb-weaver Spiders
Orb-weaver spiders are best known for spinning large and intricate circular webs. Most orb-weavers have eight eyes, with some smaller or cave-dwelling species having six. The eyes are arranged in two rows, with the front row having a much better visual acuity.
The front row’s four larger lens eyes provide orb-weavers with excellent vision to accurately navigate their delicate webs. In fact, studies suggest the legendary net-casting ogre-faced spider has the best diurnal eyesight of all known spider species studied to-date.
The smaller side eyes likely play more minor sensory roles.
So while jumping spiders have the best eyesight for hunting and wolf spiders the best night vision, orb-weaving spiders take top prize for visual acuity among web-building spiders.
Crustaceans with Multiple Eyes
Shrimps
Shrimps have complex vision systems to help them survive in their aquatic environments. They have two compound eyes on movable stalks, giving them an almost 360-degree view to spot predators and food sources.
In addition, some shrimp species have extra simple eyes called ocelli clustered together between their compound eyes. According to research, ocelli allow shrimps to detect changes in light intensity, helping them maintain circadian rhythms.
Lobsters
Lobsters have compound eyes like shrimps but also unique three additional ocelli forming a triangle pattern above their compound eyes. Scientists found that the ocelli can detect the direction a predator is approaching from through specialized receptors detecting water disturbances. This allows lobsters to quickly tail-flip away from threats detected by their ocelli before the predator even enters their wider compound eye field of vision.
Crabs
Crabs have stalked compound eyes like shrimps for detecting motion and shapes. Some crab species add on extra non-imaging photoreceptors called aesthetascs on their antennae to detect smells and light levels.
For example, blue crabs have thousands of aesthetascs giving them an enhanced “nose” and extra environmental detection capabilities.
| Crustacean | Extra Eyes | Purpose |
|---|---|---|
| Shrimps | Ocelli | Detect light changes |
| Lobsters | Triangle ocelli pattern | Detect predator direction |
| Crabs | Aesthetascs on antennae | Enhanced smell and light detection |
As we can see, crustaceans have evolved specialized extra eyes tailored to their environmental niches for better survival. Their vision capabilities continue to amaze researchers deciphering their complex biological optics systems. For more details, visit the Crustacean Research Institute online library.
Conclusion
As we’ve explored, several types of bugs, arachnids, and crustaceans have evolved with multiple eyes rather than just two. While this may seem bizarre to us humans, having numerous eyes provides crucial survival advantages for these creatures, allowing them to better monitor for food, mates, and threats in their environment.
So next time you spot an insect or crustacean, take a closer look at how many eyes it has – you may be surprised!
