The smart ones built a ship and left this planet. It smelled too much like dino farts - Chowdere

The dinosaurs didn't die, they just went home!- Ben the Messiah

they died cause they ate all the damn food. no space duh.- iamzbob

Those who weren't killed by sudden ecological change starved to death when the plants and smaller animals started dying off from sudden ecological change.- Buddy

The Earth dinosaurs were dumped here by the others of their planet in an effort to cleanse their population of the non-compliants and other undesirables. They eventually died off from the genetic defects engineered into their DNA. Just like the humans who came later. - Sporkerbelle

If you count a giant asteroid traveling through space as space travel...- fuckboy

No, Jesus Moses and Mohammad went on a weekend hunting trip and took then out with C-4 explosives......that's not fair!- Keddles

YES, it did involve space travel. The Martians came to Earth looking for a new home but they carried all sorts of bio toxins which reeked havoc on the planet and killed off countless species and eventually themselves. Though their DNA remained and that's what we evolved from.- POPTART

the dinosaurs are really the humans from the future, this is how we will mutate to finally look this way. the reason they all died out was because we found out to time travel and got stuck there and couldn't survive because we are all completely and totally dependent on technology.- Freakn

Ok I don't know this for sure, but I have a theory. The dinosaurs didn't die at all originally, they just hibernate by lying still in the middle of the desert. - Nelson the Bearded Horse

YES THEY DIED FROM THE GAS FUMES AND RADIATION. SOME WERE TAKEN AWAY BY THE ALIENS TO POPULATE OTHER PLANETS. - SANDIA