WTF Fun Fact 12753 – The Rarity of Green Eyes

We knew green eyes were rare, but they seem even more special knowing that only 2% of people in the world have them.

Green-eyed people are everywhere

But if your friend tells you their newborn has green eyes, they’re clearly seeing something different. All babies are born with some shade of brown or blue eyes. As their eyes are exposed to more light over time, their eye color begins to change into what their own unique genetics dictates. But this can take up to three years!

It may be no surprise that most people with green eyes can be found in Ireland, Scotland, and Northern Europe (or they’re descendants of people from that area). The red hair-green eye combo is pretty classic. However, anyone can technically have green eyes, including people who are Black, Arabic, Hispanic/Latino, etc.

If you were to guess the country with the most green-eyed people, would you choose Ireland? We would have. But, in fact, Iceland is the country with the largest population of green-eyed people. in fact, over 80% of Icelanders have blue or green eyes.

The myth of the Punnett square

Another interesting thing about eye color is that it’s not as simple as we learned in high school biology (remember Punnett squares?!). Genetics plays a role, but the contribution of different genes to our melanin cells (the cells that give our skin and eyes their pigment) is more complicated than we were taught. So don’t break out the paternity test as soon as you see an unexpected eye color. Even two parents with blue eyes can have a brown-eyed child!

Eye color is actually a polygenic trait (whereas Punnett squares would have had us believe it just took two genes and no more).

People with blue eyes have genes that produce the fewest melanin cells. Green-eyed people have more melanin in their eyes than blue-eyed people. But it’s the combination of that along with the presence of a yellow pigment called lipochrome that makes eyes appear green.  WTF fun facts

Source: “12 Mind-Blowing Facts About Your Body” — Newsweek

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WTF Fun Fact 12746 – Owls Don’t Have Eyeballs

Owls have eyes, of course. But owls don’t have eyeballs.

Instead, owls have eyes shaped like cylinders (with three eyelids!). Because of this shape, owls can’t roll their eyes around while keeping their heads still. That’s why they have to move their heads around too much to look around.

How do owls see without eyeballs?

According to the Office of Science & Society at McGill University: “Since moving their torsos would likely make noise that would alert their prey to their presence, owls have evolved to have necks that can spin up to 270° essentially silently.”

But why would an owl evolve to have eye rods instead of eyeballs? Wouldn’t it just be easier not to have to move your head at all in order to see to the side?

Well, perhaps, but the benefit of having eyes shaped like rods instead of balls is that not only does it allow them to see better in the dark but it’s the optimal shape for an animal with such a small skull.

The benefit of eye rods

As you may have noticed, nocturnal animals tend to have large corneas. That’s so any light can be collected more efficiently, allowing them to see in the dark.

As it turns out, these elongated eye tubes make it even easier for them to see the way they need to, even if they do have to make more movement in order to get a larger field of vision (also called binocular vision). Without moving their heads, their visual field is about 110 degrees (a human’s is 180 degrees, for comparison).

Binocular vision

Binocular vision also lets owls see objects in three dimensions (height, width, and depth). So, it turns out an owl’s eyes are pretty perfectly suited to its lifestyle.

While some believe all of this means that owls can’t see during the day because they’re blinded by too much light, that’s simply not true. Some owls can see even better than humans in the daylight as well, despite the lack of eyeballs.

At least you never have to worry about an owl giving you the side-eye. – WTF fun facts

Source: “Owls Don’t Have Eyeballs” — Office of Science & Society, McGill University

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