Today I’ve been studying about the oldest-dated fossil mammal hair. (http://news.yahoo.com/cretaceous-fur-ball-ancient-mammal-spiky-hair-discovered-132251323.html
“Cretaceous Fur Ball: Ancient Mammal With Spiky Hair Discovered”
from LiveScience.com, By Elizabeth Palermo, 10/16/2015 (updated at 3:52 p.m. EDT)
Surprise, it’s not from China! Spain has a very excellent fossil site, the Las Hoyas quarry. Back in 2011, they dug up a fossil now called Spinolestes xenarthrosus. Now a report has been published in the October 14th Nature, and LiveScience had this article about it (repeated by Yahoo). Major take-away quote:
You may think that, over the course of 125 million years, the process by which mammalian hair grows would have changed somehow, but that’s not the case, Luo said. The bones of Spinolestes, which was about the size of a small rat, are proof that ancient mammals grew hair the same way as modern mammals do.