Of all the excess baggaeg that evolution has saddled us with, we have the human toenails. They cause us problems (make life unpleasant if you don’t trim them, while wearing shoes). They also can break and split, and a hangnail can lead to a dealy infection. Why do we still have tese things?
Well in a fight you can use them to disembowel an opponent, assuming that you are a kangaroo.
All the problems you mention are the direct result of wearing shoes. Humans didn’t evolve to wear shoes but evolution hasn’t had nearly enough time to catch up with our modern lifestyle.
Are they our rather pathetic attempt to have claws?
First you must realize that not everything we end up with is an evolutionary advantage nor does it all serve a purpose. It could have served a purpose in our species’ past but that doesn’t mean it will have a clear purpose today. Take a look at the appendix, for example.
So what purpose could toenails or claws have served in our ancient ancestors? Perhaps for climbing trees, or greater dexterity for picking things up (similar to what our fingernails help us do to day).
Actually, it appears that our appendici are still functional today, as a reservoir of helpful bacteria, which re-seed the entire colon after the good flora has been wiped out by overgrowth with toxic infections such as C. Difficile, salmonella, etc.
This re-seeding is thought to improve survival rates.
Bollinger, R.R., Barbas, A.S., Bush, E.L., Lin, S.S. & Parker. W. (2007)
Biofilms in the large bowel suggest an apparent function of the human vermiform appendix.
J. Theoretical Biology. 2007.08.032
Were you drunk when you wrote this? 
Mine do a great job of cutting holes in my socks.
Please do not insult other posters in General Questions. http://boards.straightdope.com/sdmb/showpost.php?p=7697044&postcount=10 If you feel the need, take it to the Pit.
Gfactor
General Questions Moderator
Toenails are part of our mammalian heritage. Our monkey ancestors had toenails, our primate ancestors had claws, our synapsid ancestors had claws, our early tetrapod ancestors had claws.
So what if toenails don’t serve any purpose in a modern human? In order to remove our toenails there would have to be some selective pressure for toenaillessness (isn’t that a great word: toenaillessness?). But there is no such selective pressure, there is no great advantage to not having toenails. And so our toenails just sit there on the end of our useless toes that can’t even grip a tree branch.
We still have toenails, because their existence doesn’t prevent people from procreating.
They do if you clip them in bed. snik! snik! snik! snik!
Well mine stop my toes from fraying at the ends
I would have thought they served to protect your toes, where there are lots of nerve endings, and your toes get hit more often than other parts of your body (you stub your toe more often than you hit your nose or calves or anywhere else), so need that protection more.
I’m not saying that this is the main reason why we evolved toenails - that would be down to the usefulness of such nails or claws when it comes to opening seeds, fighting, cleaning bodies, etc, back when we used our feet more like hands - but perhaps they do retain some evolutionary advantage, albeit small.
WAG
This goes for both fingers and toes.
Our usage of both fingers and toes can involve somewhat extreme displacements of the soft tissue at the ends of the fingers and toes. In the case of toes it is because we don’t plant our feet squarely on the surface when running or walking but roll them untill a great deal of our weight is taken up by our little toes instead of the whole foot. The nails act like a partial exoskeleton providing support to the soft tissue allowing us to run faster.
I use the nails on my big toes to scritch annoying itches on the opposite leg or foot.
According to Kansas City Royals outfield Jose Guillen, they serve no purpose:
http://www.fox4kc.com/sports/wdaf-guillen-injury-story-022009,0,4238124.story
For some women, depending on the color of their toenail polish, it can actually help them find a mate. At certain beaches. Or so I’ve been told.
Toes are not useless! They play an important part in the motion of the foot when walking and running. Individuals who lose toes, particularly the great toe (e.g. - frost bite), often need physiotherapy to help re-learn how to walk.
:eek: YAAAGH TMI TMI TMI
Shit! Next time warn us before we click on something that cringe-worthy!
(It’s not graphic, but it’s bad enough just reading it.)