Vicious lion chair arm

I've tried to discover why there's a vicious lion in this statue of David Hume on Edinburgh's Royal Mile, but have failed. Any ideas?

It's a great detail, though, and couldn't resist a close-up.


A busy day in Ednburgh:
- St Bernard's Well was open to the public so we went for a nosey
- a walk through Dean Village (something I never did when I was a student in Edinburgh)
- Scottish National Gallery of Modern Art
- a wonderful meal at David Bann's vegetarian restaurant