Random Rhino

How do you know if there is a rhino in the pub? His bike is outside.
How do you know if there are two rhinos in the pub? There is a dent in the cross-bar.
How do you know if there are three rhinos in the pub? Stand on the bike peek in the window.
Why do rhinos paint themselves green? So they can sneak across pool tables without being seen.

More Rhino jokes here. I claim no responsibility for their quality!

I spotted this chap stuck to the side of the Informatics Forum. I don't think he's been there long because I haven't noticed him before, but I could be wrong...