h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

This only briefly mentioned in the (very informative) article, but I think it is astounding: when a rhinoceros (any species) feels threatened, it can mark its territory up to twenty (20) feet by urinating backwards. This behavior includes female rhinoceros, but they have a much shorter range.

Visitors to the San Diego Zoo will be surprised to see a sign by the rhino enclosures warning them to be quiet because of this exact reason. (Apparently, there have been a few bus tours in the history of the zoo that were just a little too loud )