It was 65 million years ago.
The Dinosaur Government was under constant fire from the public. Dinosaurs were no longer allowed to voice their opinions about the Dinosaur Act Bill of 65,674,456 BC. This caused an uproar among all dinosaurs.
The following next few weeks, a rebel group of dinosaurs grouped. Known as the Rebel Dinosaurs, they attacked the government in protest of this heresy. Unfortunately, after two years of constant civil battle among dinosaurs, the Dinosaur Government initiated a meteor strike, to cleanse the dinosaurs out for good.
Unfortunately this did not work, as many dinosaurs were able to avoid the blast altogether. The survivors formed the Dinosaur Crisis Centre, a hospital for dinosaurs with no home, and no place to go in this new world filled with humans.