Ask Dr. Universe

What are fingernails made of? Asked by Amy, 8, of Seattle.

Dear Amy,

My claws can come in quite handy when I need to scratch my ears or climb trees. I bet you’ve found that your own fingernails can be useful tools, too. Perhaps you’ve used them to pick up a penny or peel an orange.

It turns out that while my claws and your fingernails look a little different, they are actually made out of the same thing: keratin.

That’s what I discovered when I went to visit my friend Professor Lisa Carloye, who teaches biology here at Washington State University.

As you may know, your body is made up of livin...