Why are fossilized hairs so rare?
“[…] The rarity might be explained by feathers and hair containing different types of the protein keratin, which may impact the likelihood of fossilization. However, the study notes that the lack of hair samples could have nothing to do with fossilization, and be explained by the collecting behavior of paleontologists, with a single feather usually being much easier to identify than a single hair. […]” —www.sciencedaily.com/releases/…/170907142722.htm