Why does Santa have a beard but Mrs Claus doesn’t?

Men grow facial hair because 
of the stimulatory effects of male hormones like testosterone. Professor Paul Sherman of Cornell University believes that it is likely that a beard’s colour and texture played a role in ‘sexual selection’, meaning beards were useful 
for attracting mates or intimidating 
rivals. A beard could cushion a man’s 
face against blows in a fight and hide scars from previous fights.

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.