Nov 22, 2024 07:44 PM
https://www.popsci.com/science/why-do-hu...-toenails/
EXCERPTS: . . . Mammalian claws may have unfurled into flattened nails because there was some upside to the change. Our flat nails allow for wider toe- and fingertips, and at the same time provide a counter-pressure surface for our soft pads to push back against. With nails, the ends of our digits spread wider when we apply pressure, increasing the contact surface area, friction, and thus grip, explains Borths.
Though humans have mostly lost our flexible, prehensile feet as we’ve become bipedal, opposable toes actually show up earlier in the fossil record than opposable thumbs, says Borths. Our ancestors were gripping with their feet before their hands, and so toenails would have played an early role in primate climbing grip. To this day, all other contemporary primates have retained their gripping feet, he adds.
[...] Our clawless fingers and feet also make precision-grasping much simpler. Delicately plucking an insect off a leaf, for instance, is probably easier and with our soft, nailed digits over unwieldy claws. “Maybe the claws got in the way of trying to quickly reach out and grab small things,” Boyer says. One hypothesis is that nocturnal, vision-dependent insect feeding influenced primate evolution and claw loss, he notes... (MORE - missing details)
EXCERPTS: . . . Mammalian claws may have unfurled into flattened nails because there was some upside to the change. Our flat nails allow for wider toe- and fingertips, and at the same time provide a counter-pressure surface for our soft pads to push back against. With nails, the ends of our digits spread wider when we apply pressure, increasing the contact surface area, friction, and thus grip, explains Borths.
Though humans have mostly lost our flexible, prehensile feet as we’ve become bipedal, opposable toes actually show up earlier in the fossil record than opposable thumbs, says Borths. Our ancestors were gripping with their feet before their hands, and so toenails would have played an early role in primate climbing grip. To this day, all other contemporary primates have retained their gripping feet, he adds.
[...] Our clawless fingers and feet also make precision-grasping much simpler. Delicately plucking an insect off a leaf, for instance, is probably easier and with our soft, nailed digits over unwieldy claws. “Maybe the claws got in the way of trying to quickly reach out and grab small things,” Boyer says. One hypothesis is that nocturnal, vision-dependent insect feeding influenced primate evolution and claw loss, he notes... (MORE - missing details)
