# Why do goats and cats have vertical pupils, instead of round pupils? **URL:** \ **Category:** Factual Questions\ **Created:** [February 2, 2015, 5:16am UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582 "2015-02-02T05:16:19Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![steatopygia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steatopygia/32/3132_2.png) [@steatopygia](https://boards.straightdope.com/u/steatopygia)\ **Post date:** [February 3, 2015, 9:10pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/21 "2015-02-03T21:10:09Z")
This was around twenty years ago… , but I believe his pupils were very similar to cat’s eyes. I don’t think they were as misshapen as those you linked to. I never thought to check what they looked like when dilated vs. contracted. ---
**Author:** ![Nelson\_Pike](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@Nelson\_Pike](https://boards.straightdope.com/u/Nelson_Pike)\ **Post date:** [February 3, 2015, 9:43pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/22 "2015-02-03T21:43:35Z")
The big cats from cheetah and puma on up have _round_ pupils. On to purring: the puma is the only big cat that can. I don’t know if all smaller cats can do so, though. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [February 3, 2015, 9:48pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/23 "2015-02-03T21:48:28Z")
> [@Nelson\_Pike](#): > > The big cats from cheetah and puma on up have _round_ pupils. Noted in #7 above. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [February 3, 2015, 10:20pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/24 "2015-02-03T22:20:44Z")
This one looks cool, I could have lived with that eye shape, just not the bad part of the syndrome. [He got the cats’ eye.](https://images.search.yahoo.com/images/view;_ylt=AwrB8qCfNdFUKBYAlr6JzbkF;_ylu=X3oDMTIyc2VmYWo3BHNlYwNzcgRzbGsDaW1nBG9pZANjYWUzZGFiNjc1NzZjZmFkZTYwMjkyOGQ2Mzk5NjJkMQRncG9zAzkEaXQDYmluZw--?.origin=&back=https%3A%2F%2Fimages.search.yahoo.com%2Fsearch%2Fimages%3F_adv_prop%3Dimage%26va%3Dcat%2Beye%2Bsyndrome%26fr%3Dyfp-t-901%26tab%3Dorganic%26ri%3D9&w=400&h=320&imgurl=medicalimages.allrefer.com%2Flarge%2Fcat-eye.jpg&rurl=http%3A%2F%2Fmidparkshortbio67.wikispaces.com%2FCat-eye%2BSyndrome&size=+8.3KB&name=First+finding+of+%3Cb%3ECat-Eye+Syndrome%3C%2Fb%3E+%28CES%29+was+in+1898.&p=cat+eye+syndrome&oid=cae3dab67576cfade602928d639962d1&fr2=&fr=yfp-t-901&tt=First+finding+of+%3Cb%3ECat-Eye+Syndrome%3C%2Fb%3E+%28CES%29+was+in+1898.&b=0&ni=156&no=9&ts=&tab=organic&sigr=11obg4oo5&sigb=13faojvbt&sigi=11cdrjkl6&sigt=11rer2jsv&sign=11rer2jsv&.crumb=iFnxBO8CwGG&fr=yfp-t-901) 🆒 ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [February 4, 2015, 5:49am UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/25 "2015-02-04T05:49:07Z")
About the goat eyes: I’m having trouble thinking of straight-edged rectangular _anything_ anatomical. More likely in the eyes because of crystal growth planes? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 4, 2015, 2:22pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/26 "2015-02-04T14:22:52Z")
Here **Leo** : [https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&q=goat+eye&oq=goat+eye](https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&q=goat+eye&oq=goat+eye) As you can see, they’re not perfectly rectangular. But “rectangular” is a pretty good description of their overall shape. IANA biology-anybody, but I don’t think crystals have anything to do with it; AFAIK eyes don’t contain any crystalline structures. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [February 4, 2015, 5:30pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/27 "2015-02-04T17:30:50Z")
> [@LSLGuy](#): > > AFAIK eyes don’t contain any crystalline structures. No, they contain [crystallin](http://en.wikipedia.org/wiki/Crystallin) structures 🙂 ---
**Author:** ![CairoCarol](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cairocarol/32/3825_2.png) [@CairoCarol](https://boards.straightdope.com/u/CairoCarol)\ **Post date:** [February 5, 2015, 10:26am UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/28 "2015-02-05T10:26:27Z")
Wow, this discussion (especially that llama eye picture) has led me to some interesting images … and the odd thing I’ve just stumbled on is: Does/did Madeleine McCann have cat eye syndrome? Link: [Autosomal Aberrations](http://www.slideshare.net/eriiicacristobal/autosomal-aberrations-12054697) Damn, can’t get the link to go directly to the right slide - but flip to slide #28. It’s a photo of MM (and not just a similar kid, it is one of “the” photos of MM), in a presentation about genetic abnormalities. ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [February 6, 2015, 6:47pm UTC](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582/29 "2015-02-06T18:47:39Z")
[An interesting article on the purpose of various pupil shapes](http://www.koryoswrites.com/nonfiction/the-functions-of-different-pupil-shapes/). I’d heard of horses having horizontal pupils but had never noticed it in real life - I guess I just didn’t do enough horse-eye-gazing when I was a horse-mad teen. The comment about vertical slit pupils says: “A vertical pupil also allows a small predator to see horizontal movement in sharp focus- important when spotting prey from low to the ground. Spotting movement like this is of particular importance to ambush predators (like snakes, crocodiles, and small cats). It’s less useful for taller predators because their head is higher in respect to the horizontal plane of the ground.” It also says that some small canids have slit pupils - and shows a photo of a fox. Horizontal pupils are suggested to be useful for prey animals: “Perhaps one commonality in all of these creatures is that they can all be considered prey animals, and they all have their eyes located on the sides of their heads. What’s the connection? Well, as in the vertical pupils, the pupil shape and orientation can have an effect on their depth of field. In this case, horizontal pupils sacrifice some sharpness with the advantage of an extremely wide- nearly 360 degree in some species- field of vision.” [Previous page](https://boards.straightdope.com/t/why-do-goats-and-cats-have-vertical-pupils-instead-of-round-pupils/711582.md?page=1)