Dinosaurs (meaning the non-bird dinosaurs) went extinct about 66 million years ago , at the end of the Cretaceous Period, during a global mass extinction event called the Cretaceous–Paleogene (K–Pg) extinction.

Quick Scoop

  • Non-bird dinosaurs disappeared roughly 66 million years ago, when the Cretaceous Period ended and the Paleogene began.
  • This extinction is closely linked to a massive asteroid impact near Chicxulub in today’s Yucatán Peninsula, plus other environmental stresses such as volcanic activity and climate change.
  • Birds are considered a surviving dinosaur lineage, so in a strict scientific sense, dinosaurs are not entirely gone; only the large non-avian forms vanished in that event.

When it happened

  • The boundary marking this event is dated to about 66 million years ago, and rocks younger than this boundary have not yielded confirmed fossils of non-avian dinosaurs.
  • Dinosaurs had dominated Earth for well over 150 million years before this point, through most of the Mesozoic Era.

What caused the extinction?

  • Strong evidence points to a large asteroid impact that threw dust and aerosols into the atmosphere, darkening skies, cooling the planet, and collapsing food webs.
  • Additional factors, such as massive volcanic eruptions (like the Deccan Traps in India) and longer-term climate shifts, likely worsened conditions and helped drive many species to extinction.

TL;DR: Non-bird dinosaurs went extinct in a major global die-off about 66 million years ago, most likely due to an asteroid impact combined with severe environmental changes.

Information gathered from public forums or data available on the internet and portrayed here.