Ofcourse aliens would see a striking difference between humans and the other critters on this planet. No other animal has altered the planet in such a fashion as we have. We have created a quite artificial system to to continue our survival that is far removed from the activities of the natural world. Sure, ants build colonies and have a narrow social order, but they don't build rockets, publish magazines, plaster the scenery with billboards, surf the net for porn, dig through history for the sake of curiosity, or make doughnuts for that matter.