I think that the Nazca peoples, at first, were simply drawing their favourite animals as a message or tribute to the gods – the same reason they and similar cultures built elaborate temples, sacrificed babies, etc. They wanted more rain or sun or for their favourite sports team to win the big game. Just like many of these smaller Nazca lines, similar figures can be found all over other artifacts recovered from the area – clay pots and textiles covered in fish, birds, etc. It wouldn’t have taken a rocket surgeon to stumble in the desert and realize that, by dragging a foot around in the dirt, some basic drawings could be made. The many phallic geoglyphs created by modern day teenage boys in sand or snow is an obvious a testiclement to this. In terms of sequence, it’s obvious enough to tell, just by looking, that these smaller figures came before the larger geometric shapes – many of the larger lines pass right through and “cover over” the smaller shapes.
Why does it have to be aliens, you ask? Well, I’m not pulling this completely out of my arse here. There’s been plenty of evidence uncovered that screams alien involvement. The first proof I offer is a geoglyph that stands out from the rest of the smaller figures for a couple of reasons: the first being that it was created on the side of a hill, showing that it was intended to be viewed by people on the ground instead of those looking down from above; the second reason being that the figure is of a FRICKIN’ ALIEN. Look at those big, round eyes and the big dome around its head and just try and tell me it’s not some kind of space-man.
Perhaps this theory goes even further, not only providing an inspiration for the Nazca lines, but also a clue as to the mysterious disappearance of what should have gone on to be an intelligent and highly-organized civilization: once sufficiently demonstrating their abilities and dedication to their alien overlords, the Nazca peoples were all beamed up and taken away to continue their work on the surface of Mars. (picture courtesy of MarsRuins.com)
Well, mystery solved, on to Machu Picchu!