# Fish and Bird eyes

**URL:** <https://boards.straightdope.com/t/fish-and-bird-eyes/309142>\
**Category:** Factual Questions\
**Created:** [June 21, 2005, 1:10am UTC](https://boards.straightdope.com/t/fish-and-bird-eyes/309142 "2005-06-21T01:10:16Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\
**Post date:** [June 21, 2005, 1:10am UTC](https://boards.straightdope.com/t/fish-and-bird-eyes/309142/1 "2005-06-21T01:10:16Z")

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Ok, what is the white in our eyes all about; fish and birds don’t have this. How does this affect their vision and on a side question- Is there anything that connects fish and birds in relationship other than the mammals that swim.

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**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\
**Post date:** [June 21, 2005, 1:36am UTC](https://boards.straightdope.com/t/fish-and-bird-eyes/309142/2 "2005-06-21T01:36:04Z")

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It’s not just fish and birds, it’s most animals. Humans are rather unusual in having “whites” to their eyes, that is, a visible white sclera. Most mammals, including apes, do not - only the pupil and iris is exposed.

One possible function is in emotional signaling - the prominent white around the iris and pupil makes it easier to tell where someone is looking, and hence their emotional reactions.

I am not aware of any effect the white of the eye has on visual acuity.

> [@Thinktank](#):
>
> Is there anything that connects fish and birds in relationship other than the mammals that swim.

I’m afraid I have no idea what this means.

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**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\
**Post date:** [June 21, 2005, 2:23am UTC](https://boards.straightdope.com/t/fish-and-bird-eyes/309142/3 "2005-06-21T02:23:07Z")

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the second Q, is asking if birds and fish through heritage,genes,evolution etc… have an kinship to each other.

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**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\
**Post date:** [June 21, 2005, 3:42am UTC](https://boards.straightdope.com/t/fish-and-bird-eyes/309142/4 "2005-06-21T03:42:05Z")

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> [@Thinktank](#):
>
> the second Q, is asking if birds and fish through heritage,genes,evolution etc… have an kinship to each other.

Yes, but then all living organisms do.

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**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\
**Post date:** [June 22, 2005, 12:59am UTC](https://boards.straightdope.com/t/fish-and-bird-eyes/309142/5 "2005-06-22T00:59:02Z")

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Yeah, but at least birds and fish are both Vertebrates… and members of the gnathostomata.

In fact, if you’re a hard-core cladist, birds would be members of the Osteichthyes… 😉