I was surfing the Internet earlier today and came across an interesting site: WonderQuest.com.
A wise woman named April Holladay fields questions from the scientific realms along the lines of: “Can fish feel pain?” and “How fast does the world spin on its axis?” (The answers are maybe and around 500 m.p.h.)
Here’s how Holladay responded to the question, “Why are toenails thicker than fingernails?”:
“Friction and fungus thicken toenails. Toenails take a beating from socks, shoes, and generally being at the foot end of the human body where the weight bearing goes on. They’re made from the same dead skin tissue as fingernails but are two to three times thicker. Nail fungus is another culprit, affecting 30 million Americans. The fungus destroys the protective outer layer of nails (the keratin) and causes the nail to go into overproduction. The excess becomes thick, yellowed, and hard.”
She also weighed in on why we have five fingers:
“We have five fingers because our ancestors had five digits-going back at least to a mouse-sized, lizard-like beast, named Casineria kiddi, who scampered around lagoons, 340 million years ago. It's not just us. Mammals, birds, and reptiles — all have no more than five digits in their forearms.”
— Judy Lessin