Darwin, for much of early voyaging and discovering did not have a beard!
Promotions like the one at Bristol Zoo are doing it wrong!
Thanks to the photographic evidence available we know he kept himself shaved until the 1860s.
When he first published the Origin in 1859/1860 he looked like this:
Decidedly not looking like Santa Claus.
Image: Public domain. Hosted at Wikimedia Commons.
Oh, and while we are talking Beagles – if you haven’t seen it before The Beagle Project 2009