A former Disney cast member warns people not to leave their food and drinks unattended because the squirrels at Disney are VERY aggressive. They have developed super stealth ninja moves that have enabled them to even open coolers, so you have to make sure that they are latched or taped shut.
If you read the comments, they say that they have even seen squirrels UNZIP women's purses and bags to steal stuff like gum. Insane.