There's an image of Chaplin astride a hunter taking part in a boar-hunt ca.1930: he looks as if he's in charge of the horse, rather than the reverse.It would be interesting to find out just how much riding Chaplin actually did, in an era when many Hollywood names kept horses, played polo and just rode because it was the done thing.He may have ridden regularly but kept it quiet to protect his 'tramp' image.
Chaplin did have some experience riding and had stables at his studio in Hollywood (Although I don't know if any horses were ever kept there. It was eventually converted into a bungalow). According to his autobiography and his travel memoir, "A Comedian Sees The World," he was never fond of horses and was a little frightened of them. Here is more information about his boar hunt experience:http://discoveringchaplin.blogspot.com/2013/03/world-tour-1931-32-revisited-boar-hunt.html
I almost get the feeling that Charlie wasn't really into what alot of sociologist call the "elite sports" within American culture like cricket, polo and riding horses. The only "elite sports" he really seemed to enjoy was tennis. I wonder if it has anything to do with his upbringing and his poverty roots.