animal eyes

8/5/14

For something different, and a little fun, here some interesting facts about animal eyes that you may not have known.

1. Shark corneas are similar to human corneas, which is why they have been used in human transplants.
2. A worm has no eyes at all.
3. An owl can see a moving mouse more than 150 feet away.
4. Guinea pigs are born with their eyes open!
5. Scorpions can have as many as 12 eyes, but the box jellyfish has 24!
6. Camels have three eyelids! This is to protect their eyes from sand blowing in the desert.
7. Most hamsters only blink one eye at a time.
8. Owls are the only bird which can see the color blue.
9. Goats have rectangular pupils to give them a wide field of vision.
10. A scallop has around 100 eyes around the edge of its shell to detect predators.
11. Snakes have two sets of eyes – one set used to see, and the other to detect heat and movement.  They also don’t have eyelids, just a thin membrane covering the eye.
12. The four-eyed fish can see both above and below water at the same time.
13. Owls cannot move their eyeballs – which has led to the distinctive way they turn their heads almost all the way around.
14. A dragonfly has 30,000 lenses in its eyes, assisting them with motion detection and making them very difficult for predators to kill.
15. Dolphins sleep with one eye open.
16. The largest eye on the planet belongs to the Colossal Squid, and measures around 27cm across.
17. Geckos can see colors around 350 times better than a human, even in dim lighting.
18. The eyes of a chameleon are independent from each other, allowing it to look in two different directions at once.
19. A camel’s eyelashes can measure up to 10cm long, to protect its eyelashes from blowing sand and debris in the desert.
20. An ostrich’s eye is bigger than its brain.
21. Dogs can’t distinguish between red and green.
22. Polar bears have a third eyelid that helps filter UV light.
23. Human eyes are not the most highly evolved. The mantis shrimp has four times as many color receptors as the human eye and some can see ultraviolet light.
24. Pigeons can see millions of different hues, and have better color vision than most animals on earth.
25. Cat’s eyes have almost 285 degrees of sight in three dimensions – ideal peripheral vision for hunting.
26. Although color blind, cuttlefish can perceive light polarization, which enhances their perception of contrast.
27. A moth’s eyes are covered with a water-repellant, anti-reflective coating.
28. An ant only has two eyes, but each eye contains lots of smaller eyes, giving it a “compound eye.”
29. Eagles have 1 million light-sensitive cells per square millimeter of the retina – humans only have 200,000.
30. A honeybee’s eye is made of thousands of small lenses. A drone may have up to 8,600 and the queen be can have 3,000-4,000 lenses.
31. The night vision of tigers is 6 times better than humans.
32. Eyes on horses and zebras point sideways, giving them tremendous peripheral vision, to the point of almost being able to see behind them, but it also means they have a blind spot right in front of their noses.

Susan DeRemer, CFRE
Vice President of Development
Discovery Eye Foundation