Dinosaurs (the non-bird ones) lived from about 245 million years ago until about 66 million years ago, so the last dinosaurs died out roughly 66 million years in the past.

Quick Scoop

  • Dinosaurs first appeared around 240–245 million years ago in the Triassic Period.
  • They dominated Earth through the Jurassic and Cretaceous periods, together called the Mesozoic Era.
  • Non-bird dinosaurs went extinct about 66 million years ago in a mass extinction event, likely triggered by a large asteroid impact plus major climate changes.
  • That means the closest dinosaurs are about 66 million years in the past – unimaginably long before humans appeared.

Mini Timeline (Story Style)

Imagine Earth’s history as a 24‑hour day:

  1. Life starts in the sea early in the “day.”
  1. Around 10:30 p.m., dinosaurs show up during the Triassic Period, on a world with one huge supercontinent, Pangaea.
  1. Through the Jurassic and Cretaceous, continents slowly drift apart and dinosaurs spread and diversify into many forms – giant long‑necks, horned dinosaurs, fast hunters, and more.
  1. At about 11:40 p.m., 66 million years ago, a catastrophic extinction wipes out all non-bird dinosaurs.
  1. Humans only show up in the last seconds before midnight, long after dinosaurs are gone.

Why This Is a Trending Question

People still ask “how long ago were dinosaurs alive?” because:

  • New fossil discoveries keep refining the dates and details of dinosaur evolution and extinction.
  • Popular movies, games, and documentaries constantly bring dinosaurs back into the spotlight, making their time on Earth feel almost recent even though it’s tens of millions of years ago.
  • Scientists now emphasize that birds are living dinosaurs, so in a sense dinosaurs as a group never fully disappeared – only the big non-bird ones did.

TL;DR

Non-bird dinosaurs lived roughly between 245 million and 66 million years ago, with the last of them dying out about 66 million years ago.

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