Well, we know that dinosaurs are long gone (or so they say)
I just want to know what you think is the cause of their demise.

Here are some of mine
PlaguesIt could be possible that the dinosaurs got a disease that could spread fast and kill millions easily. The plague would only affect giant reptiles and such so the other species would be unharmed
Only one sex leftIn some reptiles, like the crocs, the sex of the offspring is determined by the temperature (if it's high the croc will be a male, and if it's low it'll be a female) . If a major climate change occured, and Dinosaurs functioned this way, then they won't be able to reproduce.
Magnetic Poles switching Every few milleniums the earth's magnetic poles switch (so north becomes south and south becomes north, according to the compass). If the dinosaurs had an organ or whatever which could dectect the magnetic poles in order to go to their breeding grounds, they'd be going in the wrong direction and (never find their breeding gronds).
Well, I would like to hear your theories. And I hope it's more original then "an asteroid crashed into earth, blocked out the sun which killed the plants so then all the plant-eaters died, so then all the meat-eaters died"
