Question

Is nail a vestigial organ​

Answer 1

Hmm........yupp................

Answer 2

Toe and finger nails could probably be considered more vestigial than useful. After all, they are the result of a loss of claws rather than the development of nails. They are the diminished remnants of claws that our ancestors used for capturing prey and such, a clearly beneficial feature. It is likely that the presence of claws had greater negative selective pressure to our arboreal ancestors than nails had positive selective pressure. A possible reason paws and claws became hands and nails is because, for large creatures, wrapping a hand around a tree branch and gripping it with fingers works better than trying to hang by claws stuck into it.