# Why did we evolve finger- and toenails? What purpose do they serve? **URL:** \ **Category:** Factual Questions\ **Tags:** science-math\ **Created:** [November 11, 2024, 1:15am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056 "2024-11-11T01:15:11Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Ceretarges](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@Ceretarges](https://boards.straightdope.com/u/Ceretarges)\ **Post date:** [November 11, 2024, 1:15am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/1 "2024-11-11T01:15:11Z")
I mean, I don’t see what they do that some tougher skin couldn’t do. Plus, with tougher skin on it, you wouldn’t have the issue where if you get a bruise under there it stays there for _ages_. I’d say it’s just the first thing to evolve, except it seems like tougher skin would evolve first, being less complicated. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [November 11, 2024, 1:17am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/2 "2024-11-11T01:17:31Z")
> **[Nail (anatomy)](https://en.wikipedia.org/wiki/Nail_(anatomy)#Function)** > > A nail is a protective plate characteristically found at the tip of the digits (fingers and toes) of all primates, corresponding to the claws in other tetrapod animals. Fingernails and toenails are made of a tough rigid protein called alpha-keratin, a polymer also found in the claws, hooves and horns of vertebrates. > The nail consists of the nail plate, the nail matrix and the nail bed below it, and the grooves surrounding it. > The nail matrix is the active tissue (or germinal matrix) that genera... > A healthy fingernail has the function of protecting the [distal phalanx](https://en.wikipedia.org/wiki/Phalanx_bone#Distal_phalanx), the fingertip, and the surrounding soft tissues from injuries. It also serves to enhance precise delicate movements of the distal digits through counter-pressure exerted on the pulp of the finger.[[2]](https://en.wikipedia.org/wiki/Nail_(anatomy)#cite_note-eMedicine-2) The nail then acts as a counter-force when the end of the finger touches an object, thereby enhancing the sensitivity of the fingertip,[[9]](https://en.wikipedia.org/wiki/Nail_(anatomy)#cite_note-9) although the nail itself has no nerve endings. Finally, the nail functions as a tool enabling a so-called “extended precision grip” (e.g., pulling out a splinter in one’s finger), and certain cutting or scraping actions. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [November 11, 2024, 1:18am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/3 "2024-11-11T01:18:09Z")
We didn’t evolve finger and toenails. The thing we evolved from already had them. ---
**Author:** ![Ceretarges](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@Ceretarges](https://boards.straightdope.com/u/Ceretarges)\ **Post date:** [November 11, 2024, 1:22am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/4 "2024-11-11T01:22:41Z")
Okay, then why did _they_? That doesn’t really fix things, just move it backwards to whenever they first evolved. ---
**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:** [November 11, 2024, 1:24am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/5 "2024-11-11T01:24:23Z")
Most mammals and reptiles make a lot more use of their nails than we do. ---
**Author:** ![Oly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/oly/32/8255_2.png) [@Oly](https://boards.straightdope.com/u/Oly)\ **Post date:** [November 11, 2024, 2:41am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/6 "2024-11-11T02:41:43Z")
I’ve always thought that fingernails and toenails are modifications of claws. As such they are basically vestiges of things that gave our evolutionary ancestors a great survival advantage, but are now, as said upthread, mostly superfluous. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [November 11, 2024, 3:35am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/7 "2024-11-11T03:35:44Z")
They look pretty painted sparkly pink. I actually think humans need fingernails to survive today. They can be rather deadly weapons, used properly. ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [November 11, 2024, 4:49am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/8 "2024-11-11T04:49:04Z")
We evolved fingernails shortly after becoming intelligent enough to use rocks as a hammer. That is my hypothesis. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [November 11, 2024, 4:57am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/9 "2024-11-11T04:57:13Z")
Our past claws have evolved to fingernails. Other animals continue to evolve better claws, or not , as it suits them to survive. It seems an obvious evolution to have some hard extension to ones paws/claws or whatever, if you need to dig or defend. As your evolution progresses the claws adapt. An awful lot of animals need to dig. For food. To build a den. For defence/attack. Our claws seem to have adapted very well. We do much finer work with our hands. I find that when I have clipped my nails too short, I have harder time doing a lot of things. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [November 11, 2024, 5:53am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/10 "2024-11-11T05:53:41Z")
As mentioned, fingernails are modified claws. They are a [derived character](https://evolution.berkeley.edu/glossary/derived-trait/) of all primates. Claws themselves go back to very early reptiles. Nails and claws are made by specialized epidermal cells, meaning that they are…tougher skin. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [November 11, 2024, 11:57am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/11 "2024-11-11T11:57:18Z")
> [@Darren\_Garrison](#): > > Claws themselves go back to very early reptiles Mammals aren’t descended from reptiles - but it’s likely that the basal amniote ancestor of both reptiles and mammals had claws. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [November 11, 2024, 12:11pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/12 "2024-11-11T12:11:36Z")
Many primates use fingernails to pick at parasites, including on each other as a social thing. Maybe that has guided recent evolution? ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 11, 2024, 2:24pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/13 "2024-11-11T14:24:23Z")
Most recent common ancestor was therapsids, and pelycosaurs before them … had claws. Likely the first tetrapods to evolve to slither about on land had claws. Obvious functionality to them. So the question is more why we lost full claws and stopped at the relatively vestigial nails. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [November 11, 2024, 3:05pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/15 "2024-11-11T15:05:14Z")
There is no answer to _why_ specific to an evolved characteristic. The underlying _why_ is always because of chance or an advantage to survival and reproduction. It is reasonable to ask why an evolved characteristic provides an advantage to survival and reproduction, but that doesn’t always produce a clear answer. With fingernails it could have been some ancestor of ours for no particular reason did not continue to produce the gene for sturdy claws but also had a gene that led to better brains, or perhaps stamina to point to a couple of examples. We don’t really know if the diminution of claws into fingernails provided an advantage directly, indirectly, or at all. ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [November 11, 2024, 4:09pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/16 "2024-11-11T16:09:22Z")
> [@Oly](#): > > but are now, as said upthread, mostly superfluous. Not according to the wikipedia article quoted by @Joey_P in the first reply in the thead: > A healthy fingernail has the function of protecting the [distal phalanx](https://en.wikipedia.org/wiki/Phalanx_bone#Distal_phalanx), the fingertip, and the surrounding soft tissues from injuries. It also serves to enhance precise delicate movements of the distal digits through counter-pressure exerted on the pulp of the finger.[[2]](https://en.wikipedia.org/wiki/Nail_(anatomy)#cite_note-eMedicine-2) The nail then acts as a counter-force when the end of the finger touches an object, thereby enhancing the sensitivity of the fingertip,[[9]](https://en.wikipedia.org/wiki/Nail_(anatomy)#cite_note-9) although the nail itself has no nerve endings. Finally, the nail functions as a tool enabling a so-called “extended precision grip” (e.g., pulling out a splinter in one’s finger), and certain cutting or scraping actions. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 11, 2024, 4:29pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/17 "2024-11-11T16:29:40Z")
Of possible interest to this discussion. > **[Fossils show ancient primates had grooming claws as well as nails](https://www.floridamuseum.ufl.edu/science/ancient-primates-had-grooming-claws/)** > > Humans and other primates are outliers among mammals for having nails instead of claws. But how, when and why we transitioned from claws to nails has been an evolutionary head-scratcher. > > Now, new fossil evidence shows that ancient primates –... > [@](#): > > … Now, new fossil evidence shows that ancient primates – including one of the oldest known, _Teilhardina brandti_ – had specialized grooming claws as well as nails. The findings overturn the prevailing assumption that the earliest primates had nails on all their digits and suggest the transition from claws to nails was more complex than previously thought. > > “We had just assumed nails all evolved once from a common ancestor, and in fact, it’s much more complicated than that,” said Jonathan Bloch, study co-author … > > … So, why did the ancestors of monkeys, apes and humans lose their grooming claws? One possible answer: because we have each other. > > “The loss of grooming claws is probably a reflection of more complex social networks and increased social grooming,” Boyer said. “You’re less reliant on yourself.” > > This could explain why more solitary monkey species, such as titi and owl monkeys, have re-evolved a grooming claw, he said. … > > … Why did primates develop nails at all? The question is a contentious one, but Bloch and Boyer think the transition away from claws could have mirrored changes in primate movement. As we ramped up climbing, leaping and grasping, nails might have proven more practical than claws, which could snag or get in the way … ---
**Author:** ![sunstone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunstone/32/3372_2.png) [@sunstone](https://boards.straightdope.com/u/sunstone)\ **Post date:** [November 13, 2024, 8:49pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/18 "2024-11-13T20:49:52Z")
Remember that we have the habit of assuming that our modern human ancestors lived the same way we do today. Yes, we do use our fingernails for some things, but if you were to watch a farmer or a hunter gatherer go about their different lifestyles I think you would find that nails are pretty useful to them. Peel fruit, scrape materials, split leaves to extract fibers to weave…the list goes on and on. I am pretty sure that our ancestors within just a few centuries ago found nails to be pretty darn handy. And they didn’t even have a local pedicurist to go to when needed. Fingers still give shape and structure to our fingertips, which allow us to better utilize our amazing hand abilities. As far as toenails go - even more needed than fingernails. Just because we don’t need them quite as much as in previous centuries doesn’t make them go away…evolution doesn’t work that way. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [November 14, 2024, 12:52am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/19 "2024-11-14T00:52:22Z")
> [@DSeid](#): > > Likely the first tetrapods to evolve to slither about on land had claws. Probably not, because amphibians don’t have them: > The only [amphibians](https://en.m.wikipedia.org/wiki/Amphibian) to bear claws are the [African clawed frogs](https://en.m.wikipedia.org/wiki/African_clawed_frog). Claws evolved separately in the amphibian and [amniote](https://en.m.wikipedia.org/wiki/Amniote) ([reptiliomorph](https://en.m.wikipedia.org/wiki/Reptiliomorph)) line. From: > **[Claw | Amphibians](https://en.wikipedia.org/wiki/Claw#Amphibians)** > > The only amphibians to bear claws are the African clawed frogs. Claws evolved separately in the amphibian and amniote (reptiliomorph) line. However, the hairy frog has claw analogues on its feet; the frog intentionally dislocates the tips of its fingers to unsheathe the sharp points of its last phalanges. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 14, 2024, 2:41am UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/20 "2024-11-14T02:41:05Z")
It does seem you are likely [correct](https://commondescentpodcast.com/2023/04/15/episode-163-claws/). > Claw-like structures have evolved many times in vertebrates, invertebrates, and even [plants](https://plants.ifas.ufl.edu/plant-directory/dolichandra-unguis-cati/). True claws seem to have first evolved around the origins of amniotes. Claws are rare in amphibians, but extremely common in reptiles, birds, and mammals, which suggests that early tetrapod claws might have been a key feature among the first amniotes as they explored habitats farther from the water’s edge. ---
**Author:** ![carrps](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carrps/32/2957_2.png) [@carrps](https://boards.straightdope.com/u/carrps)\ **Post date:** [November 16, 2024, 10:43pm UTC](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056/21 "2024-11-16T22:43:27Z")
Jorge Luis Borges wrote a very short essay on toe nails. I like the concluding sentence: “And when I am tucked away in Recoleta, in an ash-colored house bedecked with dry flowers and amulets, they will still be at their stubborn work, until corruption at last slows them - them and the beard upon my cheeks.” NB: Recoleta is the best known cemetary in Buenos Aires. [Next page](https://boards.straightdope.com/t/why-did-we-evolve-finger-and-toenails-what-purpose-do-they-serve/1010056.md?page=2)