Many theories exist as to why dinosaurs disappeared from Earth about 65 million years ago.
Some scientists believe dinosaurs died out due to the rapid evolution of flowering plants.
Then flowering plants appeared, replacing many of the pine trees. Dinosaurs did not have time to switch their diet to flowers and, as a result, died of starvation. Another recent and popular theory is that a giant asteroid or meteorite, as wide as 6 miles across, struck the Earth. This collision would have produced an explosive force and damage similar to that of a nuclear war. Vast amounts of dust, debris and ash would have spread quickly around the planet, blocking out the sunlight reaching Earth's surface.