Probably the most popular theory right now is the Asteroid Theory. According to this theory a large asteroid or comet collided with Earth about 65 million years ago. Scientists think that such a large collision would throw so much dust into the air that sunlight would not be able to shine and plants and animals would die. The dramatic changes in climate that resulted from this huge collision were too much for the dinosaurs. They were not able to survive.
Another theory that could explain how the dinosaurs became extinct is volcanic activity. A huge increase in volcanic activity at around 65 millions years ago could have pumped so much ash into the air that it blocked out the sun killing the dinosaurs.
Some scientists believe that there was a severe ice age. Throughout Earth's history there have been many ice ages. The last one ended about 10,000 years ago. A very severe ice age could have changed temperatures and frozen a lot of Earth's water. The dinosaurs would not be able live under such conditions and that is how the dinosaurs became extinct.
It has also been suggested that desease killed off the dinosaurs. A very deadly and contagious desease may have circulated among the dinosaurs forcing them to become extinct.
Still yet another theory is that the Earth just gradually changed in climate over a long time period and the dinosaurs were not able to adapt to the cooler, dryer climate.
There are probably other theories as to how the dinosaurs became extinct. One thing is for certain. All dinosaurs that we know of are extinct. How did all the dinosaurs become extinct? Maybe one of these theories is the right answer. However, it is difficult to explain why all the dinosaurs died out but many other animals survived. Perhaps one day we will know for certain how the dinosaurs became extinct. Until then we must speculate and continue the search for the answer to this great mystery of nature.
When a giant meteor struck the earth 65 million years ago, the impact threw up a lot of molten rock into the atmosphere. A goup of scientists used computer models and came up with the estimate that the upper atmosphere would have been heated to 2700 degrees F. Luckily heat rises, so the temperature at the ground was a lot less than 2700 deg. When the molten rock circulated in the atmosphere it rained back down to earth, and created world wide forest fires. The dinosaurs have no place to hide or run from the forest fires. Further, the temperature near the ground was heated so badly that these scientists concluded that the only animals that could survive these hot temperatures, which lasted at least several hours, were either underground or under water at the time the impact happened. Not only did the dinosaurs become extinct, an entire group of birds, known as the enantiornithine or opposite birds, were wiped out. So were the pterosaurs, the prehistoric flying reptiles. Not one enantiornithine bird or pterosaur survived.
If we look at the animals that survived the K-T extinction, the computer model of the impact makes accurate predictions, because the animals that survived were indeed either found underground (shrews, marsupial shrews, frogs, salamanders, lizards snakes, multituberculate mammals) or they were found in or near the water (shorebirds, frogs, salamanders, fish, crocodilians, turtles,duck-billed platypus). Those that cannot hide underground or underwater (enantiornithine birds, dinosaurs, marsupial mammals other than marsupial shrews, pterosaurs) would have been baked alive. Even dinosaur eggs were not buried deep enough in the ground to have survived the heat. The dinosaur eggs were hard boiled by the heat and nothing survived. We know from discoveries of dinosaur eggs that they were either laid at the surface and covered with vegetation or they were laid in shallow pits in the ground and partly covered by dirt. So, all the dinosaurs were wiped out probably within hours of the giant meteor impact. Scientists who think that dinosaurs survived the impact and later starved to death due to nuclear winter really don't know what they are talking about.
Technically they are not extinct because Alligators and Sharks were around during the dinosaur ages and Alligators I believe are a type of Dinosaur. Correct me if I am wrong but i was always led to believe an Alligator is closely related to dinosaurs.
An asteroid the size of Mount Everest struck in the Atlantic Ocean just off the tip of the Yucutan Peninsula creating what we now call Chicxulub Crater 120 miles in diameter.
The last one died.
Ha ha ha.... The best answer....
