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In interesting giraffe facts, eye size seems related to eyesight (little animals with little eyes actually can't see well), and giraffes have gigantic eyes, 10x

In interesting giraffe facts, eye size seems related to eyesight (little animals with little eyes actually can't see well), and giraffes have gigantic eyes, 10x the volume of human eyes. They are known to be able to see a human move a mile away. Other animals watch giraffe to get signals about nearby predators. Good references are hard to find, but here's a weird article that seems auto generated but also kind of useful...? https://sciencing.com/information-giraffe-eyes-8665464.html https://sciencing.com/information-giraffe-eyes-8665464.html

MichaelZuo 5y ago
Although that seems to make sense, eagles, and most birds of prey generally have smaller eyes than humans and yet they seem to have excellent sight too? Easily 20/5 vision from what I remember for bald eagles.
- ianbicking 5y ago
  Yeah, I've pondered that too. My unfounded guess is that it's that they have very good foveated vision, essentially putting all their resolution into that center region. And to be sure I'm also unclear on the optics. I think there are real physical limitations in small eyes, but presumably there are diminishing returns, and there's more than optics that define the quality of vision.
nicoburns 5y ago
> they are known to be able to see a human move a mile away I don't doubt that Giraffes have good eyesight, but being able to see a human move a mile away doesn't seem like a particularly difficult feat. A human could also do that with a clear line of sight.
- aerostable_slug 5y ago
  Really? I once had 20/10 vision as measured on my dad's eye chart (he was an MD), and I'm not sure I could always see a human moving at that distance if they were roughly the same color as the backdrop (which is, I think, a fair guess of the giraffe statistic).
usrusr 5y ago
> Other animals watch giraffe to get signals about nearby predators “Chill, giraffe seems happy" Must be a good life when everybody around you is always keen on joining your good moods

MichaelZuo 5y ago

Although that seems to make sense, eagles, and most birds of prey generally have smaller eyes than humans and yet they seem to have excellent sight too? Easily 20/5 vision from what I remember for bald eagles.

ianbicking 5y ago
Yeah, I've pondered that too. My unfounded guess is that it's that they have very good foveated vision, essentially putting all their resolution into that center region. And to be sure I'm also unclear on the optics. I think there are real physical limitations in small eyes, but presumably there are diminishing returns, and there's more than optics that define the quality of vision.

nicoburns 5y ago

> they are known to be able to see a human move a mile away I don't doubt that Giraffes have good eyesight, but being able to see a human move a mile away doesn't seem like a particularly difficult feat. A human could also do that with a clear line of sight.

aerostable_slug 5y ago
Really? I once had 20/10 vision as measured on my dad's eye chart (he was an MD), and I'm not sure I could always see a human moving at that distance if they were roughly the same color as the backdrop (which is, I think, a fair guess of the giraffe statistic).

usrusr 5y ago

> Other animals watch giraffe to get signals about nearby predators “Chill, giraffe seems happy" Must be a good life when everybody around you is always keen on joining your good moods