I did a short history piece for STV Edinburgh on Bum the Dog quite a few years ago - they have a reciprocal Greyfriar's Bobby in San Diego, which is right beside their Bum, and much more prominent than our Bum, who is really unfairly tucked away.
Bum was so famous in San Diego, as the original littlest Hobo, who would be fed by all and sundry in the city, that his image was used on dog licences at the time. It's a really interesting tale.
The end of my piece for STV got edited out. I had the marvellous closing line of, "Hopefully more people will seek out the statue, now that we've got to the bottom of Bum." They really didn't like so many references to 'Bum' (though were fine with references to presumed homosexuality simply because a chap was effeminate in a piece about the Craigentinny Marbles).