Paul James asked:
I pick my nails. How long do the discarded nail fragments last?
Kat asked Andrew Holding for an answer to this question...
Andrew - So one, yes you're right. Itís disgusting. Do not do this. Some poor personís having to clean up behind you around the world. So, itís keratin that makes up your fingernails. So, thatís actually quite hard to break down. Itís not something that biology really evolve for to live off fingernails which is, I'm kind of grateful for. So if you ate them, you couldnít digest them. So thatís not Ė people arenít going to be eating them. Not many things in the world do really so theyíll sit around for a while.
Kat - And there are mummies with hair and nails and stuff like that.
Andrew - So, I was at the British Museum recently and my daughter was looking at this mummified corpse. It was mummified because itís just been sat in the desert. It wasnít an Egyptian one. She just said, ďDaddy! It still got hair.Ē I had to explain to her that it was actually a person who sat there for 5,000 years.
Kat - Ewe! DavidÖ
David - Well, I'm a geologist and I know keratin is a molecule which fossilises. You can extract fossil molecules of keratin from dinosaurs. So weíre talking 150-million-year-old keratin. I donít think fingernails would survive that long but the stuff of which itís composed can be found in the fossil record.
Kat - Wow! Do you know if dinosaurs ate their fingernails? Did dinosaurs have fingernails?
David - They probably ate other dinosaurís fingernails.
Andrew - They do have claws which is kind of similar.
David - And feathers.