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Old 05-10-2016, 12:58 PM
Machine Elf Machine Elf is offline
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why do we have fingernails instead of claws?

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?
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Old 05-10-2016, 01:05 PM
Senegoid Senegoid is offline
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Especially retractable claws (or fingernails). Why can't we have that too?
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Old 05-10-2016, 01:08 PM
Morgenstern Morgenstern is offline
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Especially retractable claws (or fingernails). Why can't we have that too?
Makes it way too hard to pick your nose.
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Old 05-10-2016, 01:10 PM
Machine Elf Machine Elf is offline
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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.
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Old 05-10-2016, 01:16 PM
leahcim leahcim is offline
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I've read that having flat fingernails gives some rigidity to the fingertip, which is useful for grasping.
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Old 05-10-2016, 01:16 PM
Colibri Colibri is offline
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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.

Some other animals that climb using opposable digits like opossums have a nail on the thumb but claws on the other digits.
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Old 05-10-2016, 01:48 PM
Atamasama Atamasama is online now
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Originally Posted by Machine Elf View Post
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.
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Old 05-10-2016, 03:37 PM
panache45 panache45 is offline
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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.
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Old 05-10-2016, 05:05 PM
Jophiel Jophiel is online now
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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?

Last edited by Jophiel; 05-10-2016 at 05:06 PM.
  #10  
Old 05-10-2016, 05:31 PM
panache45 panache45 is offline
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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.
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Old 05-10-2016, 05:52 PM
puzzlegal puzzlegal is online now
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Eh, the odds are that nails to claws was advantageous.
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Old 05-10-2016, 07:35 PM
Jophiel Jophiel is online now
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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

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.
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Old 05-10-2016, 07:49 PM
Hail Ants Hail Ants is offline
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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.
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Old 05-10-2016, 07:53 PM
Colibri Colibri is offline
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Originally Posted by panache45 View Post
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.

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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.
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Old 05-10-2016, 07:58 PM
Colibri Colibri is offline
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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.
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Old 05-10-2016, 11:24 PM
Raguleader Raguleader is offline
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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.
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Old 05-11-2016, 12:25 AM
Isamu Isamu is offline
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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?
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Old 05-11-2016, 03:13 AM
Isilder Isilder is offline
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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!"...
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Old 05-11-2016, 05:15 AM
Lukeinva Lukeinva is offline
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Because we trim our nails. If we didn't they'd grow into claws.
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Old 05-11-2016, 06:00 AM
Chronos Chronos is offline
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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.
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Old 05-11-2016, 08:01 AM
Jonathan Chance Jonathan Chance is offline
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A man can dream!
  #22  
Old 05-11-2016, 09:47 AM
Colibri Colibri is offline
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* More important ... being able to use weapons and tools.. back to those rocks...
Probably not a major consideration for lemurs, bushbabies, and tarsiers.

Once again, we have nails because our ancestors had them. They evolved tens of millions of years before the first tools were made. Tool use was not a consideration in their evolution.
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Old 05-11-2016, 09:47 AM
Doughbag Doughbag is offline
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The function of a nail is different to a claw.

The claw is an aid in gripping to surfaces and holding prey in place or a weapon altogether.

The nail is there to protect your fingertips (or in some mammals it turned completely into a hoof) and as a tool to hold or pull small things (splinter) that would not be possible to do with claws.

Just think of the things we do and touch with our hands and the fingers attached to them, some of those activities or places where they touch - I certainly wouldn't wanted claws anywhere near there.
  #24  
Old 05-11-2016, 01:35 PM
furryman furryman is offline
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Because we trim our nails. If we didn't they'd grow into claws.
I always wonder how that East Indian guy grew the world's longest fingernails. He must have had somebody do everything for him. Mine break off all the time.
  #25  
Old 05-11-2016, 03:40 PM
Chronos Chronos is offline
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In fact, I think that was the point of the exercise: By growing such long nails, he's proving that he has people to do things for him. It's a status symbol.

And while tools didn't drive the evolution of fingernails, it's possible that our pre-existing fingernails were one of the traits that enabled us to become the premier tool-users on the planet.
  #26  
Old 05-11-2016, 07:57 PM
Senegoid Senegoid is offline
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In fact, I think that was the point of the exercise: By growing such long nails, he's proving that he has people to do things for him. It's a status symbol.
OTOH, I have a friend, about my age, comfortably (financially) retired, who is growing claws to rival Howard Hughes's legendary talons. He's become horribly depressed in recent years, and I think he's simply not taking care of himself. (There's much other evidence of that too.)
  #27  
Old 05-12-2016, 11:51 AM
furryman furryman is offline
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In fact, I think that was the point of the exercise: By growing such long nails, he's proving that he has people to do things for him. It's a status symbol.

And while tools didn't drive the evolution of fingernails, it's possible that our pre-existing fingernails were one of the traits that enabled us to become the premier tool-users on the planet.
Actually, I read somewhere that being in the Guinness is a very popular hobby in India. Maybe status plays into it as well.

Last edited by furryman; 05-12-2016 at 11:53 AM.
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