Dinosaurs lived for roughly 160 million years, when we think about the climate they lived in, we often assume it was either hot and dry, or hot and muggy. In fact it was both, depending on which era we are referring to. Over the course of 160 million years changes did occur reshaping the earths surface, its vegetation, and climate. Let us examine what the climate was like during the three eras of the great beasts known as “The Dinosaurs”.
-Triassic Period-
This was when the first dinosaurs appeared; it began 248 million years ago. The earth was one large land mass surrounded by a huge ocean. This super continent was called Pangaea. There were no ice caps. Except for coastal areas, much of the land was indeed hot and dry. There were frequent violent monsoons. Temperatures were in the mid-to-high 30’s Celsius, (80’s Fahrenheit) with very little fluctuation.
-Jurassic Period-
This period began 190 million years ago. It saw the separation of the large land mass into two bodies of land. Laurasia was to the north and Gondwana was to the south. Rivers and lakes formed, and the climate, although still hot, was now humid with periods of heavy rainfall. Temperatures were in the mid-30’s Celsius (80’s Fahrenheit) with only some small fluctuations.
-Cretaceous Period-
This period was from about 144 million years ago to 65 million years ago. Most dinosaur life flourished at this time, there were more species and more animals. The period ended with the large mass extinction of the dinosaurs. This time is also when flowering plants started to develop and spread.
The continents continued to break up, forming a more familiar look to what we have today. The temperatures started to fluctuate, if only slightly; the overall climate was still hot and humid. Temperatures averaged about 4 degrees hotter than they are today.
-Oxygen Levels-
It is very likely that the air at the time of the dinosaurs had a higher oxygen content. This has been shown by scientists who studied air bubbles found in fossilized amber. They found examples where the oxygen levels were 38%, compared with today’s oxygen levels of about 19%-21%. This probably helped the dinosaurs to grow and reach the massive sizes they did.
-Summary-
We have learned that different dinosaurs lived in slightly different climate conditions depending on when they lived. Climate also impacted where they lived and what they ate. When the planet experienced more rain fall, it gave rise to more plant life, thus increasing dinosaur numbers, as well. Keep in mind that although day time temperatures were hot, night temperatures were cooler, this enabled the evolution and development of new animals, such as mammals, who could keep warm with fur and be active in the cooler nights.
Sources http://dinosaurs.about.com/od/dinosaurbasics/a/dinosaurages_2.htm
http://www.trufax.org/general/oxygen.html
