Then of course you have these 'fellas'... Problematic to the point of being regarded as vermon - The infamous Vervet Monkey...

http://en.wikipedia.org/wiki/Vervet_monkey

Under no circumstances do you leave your tent flap open or unzipped if there's nobody around, or leave you back-pack unattended. They'll go in and literally destroy everything in an attempt to find food.

This one is maybe 3 meteres away from me. They are not easily intimidated and have been known to bite children while stealing a sweet or something. Of course this guy is rather proud of himself as you can see...