# why do we have fingernails instead of claws? **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2016, 5:58pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496 "2016-05-10T17:58:13Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [May 10, 2016, 5:58pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/1 "2016-05-10T17:58:13Z")
Humans, chimps, and gorillas (and I suppose some other primates I don’t know about) all have fingernails instead of claws. Claws actually seem pretty useful, so why did we evolve away from them? ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [May 10, 2016, 6:05pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/2 "2016-05-10T18:05:46Z")
Especially _retractable_ claws (or fingernails). Why can’t we have that too? ---
**Author:** ![Morgenstern](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Morgenstern](https://boards.straightdope.com/u/Morgenstern)\ **Post date:** [May 10, 2016, 6:08pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/3 "2016-05-10T18:08:38Z")
> [@Senegoid](#): > > Especially _retractable_ claws (or fingernails). Why can’t we have that too? Makes it way too hard to pick your nose. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [May 10, 2016, 6:10pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/4 "2016-05-10T18:10:32Z")
> [@Morgenstern](#): > > Makes it way too hard to pick your nose. I’d probably be willing to trade that for the ability to slash through packing tape (or potato chip bags) without a knife. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [May 10, 2016, 6:16pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/5 "2016-05-10T18:16:04Z")
I’ve read that having flat fingernails gives some rigidity to the fingertip, which is useful for grasping. ---
**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:** [May 10, 2016, 6:16pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/6 "2016-05-10T18:16:32Z")
Probably because our primate ancestors relied on opposable thumbs (and toes) to climb instead of climbing with claws like squirrels. They climbed mainly on smaller branches that they could get their entire hands around, rather than clinging to trunks by claws. With such a climbing strategy long sharp claws just get in the way. Most primates, even primitive ones, have nails instead of claws on their digits, although lemurs retain a claw on one toe for grooming. Marmosets, which climb up trunks like squirrels,[have claws on most toes but have a nail on the thumb.](https://s-media-cache-ak0.pinimg.com/736x/2b/1b/4a/2b1b4ab6c6d2d9301eabde165c734a7c.jpg) Some other animals that climb using opposable digits like opossums[have a nail on the thumb but claws on the other digits.](http://www.ibiblio.org/carrborocitizen/mill/wp-content/uploads/2011/12/Fauna3.jpg) ---
**Author:** ![Atamasama](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atamasama/32/12961_2.png) [@Atamasama](https://boards.straightdope.com/u/Atamasama)\ **Post date:** [May 10, 2016, 6:48pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/7 "2016-05-10T18:48:46Z")
> [@Machine\_Elf](#): > > I’d probably be willing to trade that for the ability to slash through packing tape (or potato chip bags) without a knife. With bulky claws you’d have trouble holding a knife, or a gun. I feel more confident in my ability to use tools, thanks. Grow out and maintain one fingernail and you can use it for simple things like opening chip bags and packing tape. You don’t need to be Wolverine to do that. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 10, 2016, 8:37pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/8 "2016-05-10T20:37:52Z")
And why don’t we have wings or infra-red vision, while we’re at it? Evolution doesn’t work that way. It doesn’t decide that something is better, then evolve toward it. If a given mutation doesn’t occur, it doesn’t happen. ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [May 10, 2016, 10:05pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/9 "2016-05-10T22:05:46Z")
> [@panache45](#): > > And why don’t we have wings or infra-red vision, while we’re at it? > > Evolution doesn’t work that way. It doesn’t decide that something is better, then evolve toward it. If a given mutation doesn’t occur, it doesn’t happen. True, but if we evolved from little rat creatures or something similar then it seems likely that our proto-primate ancestors at some point went from claws to nails. So the question then is why were nails advantageous enough to become the norm? ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 10, 2016, 10:31pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/10 "2016-05-10T22:31:36Z")
> [@Jophiel](#): > > True, but if we evolved from little rat creatures or something similar then it seems likely that our proto-primate ancestors at some point went from claws to nails. So the question then is why were nails advantageous enough to become the norm? There’s a logical step missing in your thinking. Hint: “went from claws to nails” does not necessarily imply “advantageous,” apart from other possible factors. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [May 10, 2016, 10:52pm UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/11 "2016-05-10T22:52:59Z")
Eh, the odds are that nails to claws was advantageous. ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [May 11, 2016, 12:35am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/12 "2016-05-11T00:35:08Z")
> [@panache45](#): > > There’s a logical step missing in your thinking. Hint: “went from claws to nails” does not necessarily imply “advantageous,” apart from other possible factors. If you’re going to answer questions, then answer them instead of giving too-cute “hint” nonsense to let everyone know how smart you are :rolleyes: Asking why we don’t have wings or infrared vision isn’t the same because there was never a point along our known evolutionary chain where we DID have wings. So while it might be handy to have wings or six arms or acid breath, it’s not the same as asking why we went from a trait _we used to have_ (claws) and adapted to have a different trait (nails) instead as our primate ancestors evolved. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [May 11, 2016, 12:49am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/13 "2016-05-11T00:49:17Z")
I would hazard a guess that it has something to do with primates not being carnivores. And proto-humans only became major carnivores (or omnivores) by way of tool-making and weapon building, something that claws are a detriment to doing. ---
**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:** [May 11, 2016, 12:53am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/14 "2016-05-11T00:53:45Z")
> [@panache45](#): > > And why don’t we have wings or infra-red vision, while we’re at it? > > Evolution doesn’t work that way. It doesn’t decide that something is better, then evolve toward it. If a given mutation doesn’t occur, it doesn’t happen. This is not particularly insightful. In this case, these are just two forms of the same structure, not an entirely de novo organ. It’s entirely reasonable for nails to have evolved from claws without any major mututaion. > [@panache45](#): > > There’s a logical step missing in your thinking. Hint: “went from claws to nails” does not necessarily imply “advantageous,” apart from other possible factors. Yeah, in this case it pretty much does. Read my post. We can identify the reasons that primates don’t have claws. There’s a whole field of evolutionary biology predicated on the idea that we can identify the reasons why particular characters evolve. ---
**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:** [May 11, 2016, 12:58am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/15 "2016-05-11T00:58:41Z")
> [@Hail\_Ants](#): > > I would hazard a guess that it has something to do with primates not being carnivores. And proto-humans only became major carnivores (or omnivores) by way of tool-making and weapon building, something that claws are a detriment to doing. No, many prosimians, similar to ancestral primates, are mainly insectivores and also eat small vertebrates. Claws would be useful for catching prey. And there are many tree climbing non-carnivores like squirrels that have claws. Nails evolved in ancestral primates due to their climbing style, not diet. ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [May 11, 2016, 4:24am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/16 "2016-05-11T04:24:36Z")
My understanding of evolution is that certain traits evolve because they did not actively prevent individuals from getting laid. So it’s safe to say that humans and other primates have claws because somewhere back in our developmental tree, it was decided that amorous claw marks were best avoided. ---
**Author:** ![Isamu](https://avatars.discourse-cdn.com/v4/letter/i/7c8e57/32.png) [@Isamu](https://boards.straightdope.com/u/Isamu)\ **Post date:** [May 11, 2016, 5:25am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/17 "2016-05-11T05:25:36Z")
> [@Colibri](#): > > There’s a whole field of evolutionary biology predicated on the idea that we can identify the reasons why particular characters evolve. Why did Bert and Ernie evolve? To fill an empty void in our lives? ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [May 11, 2016, 8:13am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/18 "2016-05-11T08:13:33Z")
> [@Colibri](#): > > Probably because our primate ancestors relied on opposable thumbs (and toes) to climb instead of climbing with claws like squirrels. They climbed mainly on smaller branches that they could get their entire hands around, rather than clinging to trunks by claws. With such a climbing strategy long sharp claws just get in the way. > > Most primates, even primitive ones, have nails instead of claws on their digits, although lemurs retain a claw on one toe for grooming. There’s a few more important points… - being able to climb more things. Not just trees, its vines , rocks, muddy slopes and so on. - More important … being able to use weapons and tools… back to those rocks… Being attacked by a tiger ? or large dumb primate ? pick up a weapon… As ACC said (and DNA references) 'bang the rocks together guys!"… ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [May 11, 2016, 10:15am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/19 "2016-05-11T10:15:40Z")
Because we trim our nails. If we didn’t they’d grow into claws. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 11, 2016, 11:00am UTC](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496/20 "2016-05-11T11:00:50Z")
There’s a difference between a long fingernail and a claw. Claws are narrower, thicker, more curved in cross-section, and pointier. No matter how long you let a fingernail grow, it’ll never get those traits. [Next page](https://boards.straightdope.com/t/why-do-we-have-fingernails-instead-of-claws/754496.md?page=2)