When Did Dinosaurs Become Extinct


When did dinosaurs become extinct? Well, way before we were born is the usual thought process of most and the matter is left untouched, unresolved. But what of the curious minds who want a definite answer? This is the article for you. We will explore all there is to know about these majestic species. We will discover when they became extinct, as well as take a look at the most popular theories and hypotheses on why and how did they die out.

Through this article, and perhaps in life in general, it is important to keep in the back of our heads how small, how miniscule the human existence has been when peeked at through the lens of the grand scheme of things. For all our might, all our technology, all our booming civilizations and culture, we are akin to flies in our species lifespan when compared to that of these reptiles of old.

When Did The Dinosaurs Die Out

Most scientists, up until 2008, had settled that dinosaurs died out at the end of the Cretaceous period, at approximately 65.5 million years in the past, give or take a few hundred thousand years. However, in 2008, Scientists of the University of California, Berkeley, managed to specify the date of the reptile species death rattle much more accurately, by using and refining a technique commonly used for dating fossils and rocks: The so called ‘argon-argon dating method”.

According to them, the last of the dinosaurs became extinct about 65.95 million years ago – give or take 40.000 years. Now, obviously, this does not seem quite so accurate to most of us, even if it does narrow down the previous estimate considerably. This is because we are used to counting years by our own lifespans. When put on the grand scheme of things, however, this is quite insignificant. Dinosaurs reigned dominant for a very impressive stretch of time – certainly lengthier and more significant tan our own. It took many millions of years before we even appeared on Earth, after they had long gone extinct.

How Did They Become Extinct

So, if they were that big of a success as a species, how did they end up disappearing, after all? Quite extraordinarily, more than half of the world’s species were obliterated during that period. What marked the end of the Cretaceous period and the beginning of the Paleogene remains a scientific mystery to this day. What is certain, however, was that while all kinds of dinosaurs, even the plesiosaurs of the seas and pterosaurs of the skies went extinct the vast majority of mammals, turtles, frogs and even crocodiles survived the disaster. Birds, likewise, survived, and so did some underwater species. Finally, plants, those that were capable of withstanding climate extremes at least, also managed to do okay.

Scientists have brought up a number of hypotheses on what kind of disaster really hit Earth during that period. So far, there has been no conclusive evidence for any of these trains of thought. The nature of the calamity that struck dinosaurs remains to this day largely unsolved, a mystery we can not yet uncover for certain.

Popular Hypotheses

The most popular hypothesis and leading theories on dinosaur extinction are the following:

  • Food chain imbalances lead to their starvation.
  • Various diseases struck them heavily, wiping out entire populations of them.
  • Volcanoes spewed ash and gas, suffocating many.
  • A big meteorite crashed into Earth, drastically changing the planet’s climate, so that they could no longer survive.

Of these theories, the last two seem to be the most likely. The meteor crash hypothesis has its origins in the discovery of rock layers rich in iridium, dated during the precise period of dinosaur extinction. These layers are spread all over Earth, on both land and water. Now, if we couple that with the fact that iridium is extremely rare on Earth and yet abundantly rich in meteorites, we can understand the scidntists’ jump that a comet or asteroid struck the planet and scattered iridium worldwide. In addition, an appropriately sized crater was found and dated to that period in Mexico’s Yucatán Peninsula, called Chicxulub, which adds further credit to the theory.

An alternative interpretation, is that the Earth’s core – the source of magma – is also rich in iridium. Instead of a meteor crash, massive volcanic eruptions could have spread iridium around the world – as well as deadly, sunlight blocking dust, and suffocating gas. Like with the previous theory, scientists’ have found traces of such an event, this time in India, that dates back to roughly 65 million years ago, the period of dinosaur extinction.

There is no easy way to decide which of the two hypothesis is closer to the truth. Both have their merits. Perhaps both contributed to dinosaur extinction, or perhaps dinosaurs died out for different reasons altogether. But did they, really?

Dinosaurs and Birds

According to recent research, there might be a still a few surviving dinosaur species, flying around us even to this day. Or, well, to put it more accurately, at least their close descendants do. Up until recently, modern birds seemed to appear rather suddenly, in a snap of evolutionary time. New findings suggest there was a long series of evolutionary changes at play, tracing their origins to the group of two-legged dinosaurs known as theropods. Naturally, the process was gradual, with bird features evolving one by one this type of dinosaurs.


Evidently, there is a lot of meat still in the story of dinosaurs. What exactly struck them down and made them go extinct? How did they not survive when other, seemingly lesser species managed well enough? Most importantly, how and why did a Tyrannosaurus Rex shrink down to a bird? These questions have no easy answers. What is certain, however, is that the mysteries of dinosaurs remain attractive to us to this day. And perhaps for good reason. There have been other species that were completely dominant on Earth before us, for far longer than we do, and we would do well to understand what put an end to their reign.