Why did the dinosaurs become extinct?

7 Answers
Did they turn into birds? How? Birds are small dinosaurs were huge?

There are many theories about how and why dinosaurs became extinct. The fossil record shows that they disappeared about 65 million years ago at the end of the Cretaceous Period.

In rocks of this age, a tiny layer of Iridium has been found. Iridium is found in high concentrations in meteorites so from this observation came the idea that a large meteor hit the Earth and wiped out the dinosaurs. The remains of a large crater have been found in the gulf of Mexico and it is believed the meteor impact occurred there. Such an impact would have launched tons of dust in the atmosphere, blocking out the Sunlight, leaving many plants and animals (including dinosaurs) to die.

Another theory is that gradual climatic changes caused the extinction of the dinosaurs. These reptiles were adapted to live in a tropical environment. When the environment changed into a colder climate, they were unable to survive and died off in great numbers. Earth's climate is continuously changing so this scenario is not unlikely and doesn't require massive extraterrestrial impacts to explain the disappearance of the dinosaurs.

As with your comment about birds: Not all dinosaurs immediately died in a single moment at the end of the Cretaceous. Some small ones were able to survive and evolved further into birds. In fact, these dinosaurs probably already looked a lot like birds when their bigger relatives still roamed the Earth. They just didn't have a change to become a dominant species until after the extinction events.


The term dinosaur means "terrible lizard". The creatures we usually refer to today as dinosaurs were reptiles, just like those we see around us today, except they were able to live much longer and some eventually grew much larger than our modern day lizards.

Animal species become extinct for many reasons. There can be genetic defects that spread to the entire group, weakening the species and causing them to die out.

Another cause is change in habitat. If a particular type of dinosaur depended solely on plant life for food, history tell us the earth went through a climate change which would have cut back on the available plant foods for herbivores. This loss of food could result in extinction.

A drop in temperature similar to the Ice Age, might also have caused the death of a species of cold-blooded animals like dinosaurs.

So, there are many reasons why the largest of the reptile species became extinct, and the extinction of one type might have had a different cause from the extinction of other types.


Dinosaurs died out around 65 million years ago. There are many theories attempting to explain why this happened. The most widely accepted is that a giant asteroid crashed into earth (near the Gulf of Mexico according to researchers) and caused catastrophic changes to the climate. As a result the environment was hostile to the dinosaurs and they died out. There's still a problem with that theory though. Paleontologists haven't found dinosaur skeletons in rocks dating to the period of impact. In fact, there is some evidence that suggests that the dinosaurs had died before that impact.

Here are some less popular theories:

- A diseases wiped out the entire population of dinosaurs.
- multiple causes lead to this mass extinction event. This scenario combines three major postulated causes: volcanism, marine regression, and extraterrestrial impact.


I don't have any statistics or fancy words but my professor said they died off mainly because of the food chain
The "meteor " hit the earth and caused a chain of eruptions (volcanic of course) and the ash cloud covered the earth killing plants switch out plants it killed the herbivores and with out herbivores well the carnivore didn't stay so long either in witch they started eating their own kind and even their selves the one who stayed on the earth the longest had to have been the cockroaches mainly because they can eat almost any thing and the omnivores who for those that don't know can eat just like humans plants and animals and. Sry for suck a long response :)


Dinosaur become extinct because as per researchers / palaeontologists, the meteorite that hit the earth causing a massive pollution followed by the calamities such as eruption and later on by ice age period, well they couldn't really survive due to drastic climate change and no sunlight for them as well as trees.

But is is to be noted that the tiny mammals did survive and still nowadays they are here like rats etc, but a little modification upon their sizes due to adaptation of the new life cycle.

But no one can really say that all of them did got extinct as some places or islands still not yet explored.


Shortly before the last dinosaurs died, 65.5 million years ago, some did start evolving into birds, it was specifically the Therapod dinosaurs that were making this evolutionary change. Also you must remember not all dinosaurs were huge, some were tiny, not all birds were small, some that have gone extinct were huge, such as the Moa.

Most certainly some dinosaurs did evolve into birds, but the rest were killed in what we call the KT extinction event which we believe was caused by a meteor hitting the earth. Also you need to be aware that there were many extinctions prior to this last one.


Maybe dinosaurs lived at the same time as man and maybe man killed them because the dinosaurs were big and man was frightened.