Scientists have recently discovered that the sensitivity of our touch is due to the ridges in our fingertips. Previously, it had been assumed that their sole purpose was to enhance our ability to grip things, presumably not to assist in finding criminals.
Researchers inserted tungsten electrodes into the main nerve of volunteers’ arms. Then they took a card covered with tiny flat- tipped cones—less than half a millimeter high— and stroked the fingertips in different directions varying the speed.They were able to record the activity of single nerve cells, and their locations. The location of the dubbed hot spots matched the pattern of the ridges, which are only .4 millimeters high.
Dogs and other animals do not have ridges on their paws nor are their prints unique. However, dog nose prints are unique because of their bumps and holes. I don’t know if anyone has ever tested whether these contribute to their sensitivity of touch. Given that dogs have superior sense of smell, they shouldn’t need to poke their noses where they do to get a whiff so maybe they are checking out texture as well as smell.
On the other side of our fingertips are our nails. I claim fingernails as my favorite tool for scraping and getting into thin places.
Of course if we got into fingers I could write a long essay of their uses, even individual fingers for communication. I’m suddenly reminded of a story about a man whose hand had been mangled. It was reconstructed including reattaching appropriate nerve endings. Unfortunately, a couple of nerves were swapped such that if the man went to thumb rides, he would give drivers the third finger salute. Ala Dave Barry, I am not making this up.