Note: Not all of these theories are widely accepted by scientists and everyone else.

10. Nuclear Attack
Although very unlikely, a natural nuclear assault on a prehistoric Earth has a very slim chance of actual occurring. Possible sources could be from the sun or a nearby comet.

9. Mega-Tsunami
A very large wave may have wiped out the dinosaurs by spreading water and bringing massive floods all over the land-based continents, while murdering all life in its path. Jumbo tsunamis are usually caused by earthquakes from underneath the surface floor of the ocean.

8. Widespread Poisoning
It is possible that the dino water supply became infested or a poisonous plant grew and spread exponentially.

7. Alien Genocide
Perhaps one of the more less thought of probabilities construes us to consider extraterrestrial involvement in Earth’s History. It is possible that billions of years ago, an unknown race of extraterrestrials visited the planet and committed mass slaughter towards life for a variety of reasons, such as maybe they planned to colonize or terra-form the planet, or they could have just intended to perform a science experiment while conducting tests on different species of life.

6. Supervolcano
An eruption from a prehistoric supervolcano (comparable to modern-day Yellowstone) would send enough smoke and ash into the sky long enough to block out sunlight and oxygen to eradicate most forms of plant life, and after the plants die, animals will follow soon thereafter.

5. Nearby Supernova
A relatively unheard of phenomenon, supernova explosions can generate massive gamma ray bursts which affect everything around the dying star. As long as the event occurs in the right place at the right time, the Earth’s ozone atmosphere and organisms living all over the planet would be sufficiently wiped out from aftereffects such as radiation poisoning.

4. Worldwide Epidemic
A fast-growing disease or plague could have possibly exterminated the dinosaurs from within, and without modern medicines, the animals would not stand a chance against the biological or chemical attack, however the source of such a deadly plague is unknown, perhaps from a space meteor or a form of methane gas from the ocean floor.

3. Starvation
Another farfetched theory may arise from the fact that the dinosaurs may have run out of food. Perhaps the ecosystem became unbalanced and all the herbivores died, which means no food for the carnivores. Or maybe a breed such as the Tyrannosaur or Velociraptor quickly grew to overpopulation.

2. Global Climate Change
Another possible conclusion to arrive at, climate change could kill off the dinos before they had a chance to adapt to the extreme weather modifications. Similar to the movie “The Day After Tomorrow”, rapid fluctuations in climate would have been difficult to combat.

1. Asteroid Strike
The most widely accepted theory of dinosaur extinction is that a city-sized asteroid collided with the Earth somewhere in the Yucatan peninsula located in present-day Mexico.