For tens of millions of years after the dinosaurs first appeared on Earth, they didn’t like the tropical regions and avoided it as best as they could.
Until now, researchers didn’t really know why dinosaurs didn’t like the tropics and moved towards south and north of the equator.
A team of scientists conducted a new study which suggests that the tropics were extremely hot and dry, and the high levels of CO2 kept the dinosaurs, including the massive herbivores, away from the tropics for about 15 million years.
According to the researchers smaller carnivorous dinosaurs started to inhabit the tropics about 200 million years ago, but the big plant eaters stayed away from it for longer.
The paleontologists found that dinosaurs didn’t like the tropics because the climate back then changed radically from periods of extreme drought and very high temperatures to intensely wet weather.
Also, there were wildfires that obliterated all the vegetation, which left the herbivores with nothing to feed on.
Researchers published their recent findings in the journal Proceedings of the National Academy of Sciences.
Randall Irmis, a researcher at the University of Utah and one of the lead authors of the study, said their data suggest the tropics back then were not a “fun place”.
Irmis added that the large herbivore dinosaurs could not have existed close to the equators mostly because the weather conditions were so extreme that there wasn’t any dependable vegetation food for them.
The researchers said the tropics more than 200 million years ago were nothing like the tropics we have today.
Jessica Whiteside, scientist at the UK’s University of Southampton, said that the weather conditions of the tropics would have resembled the arid western regions of United States today.
The fluctuating climate and the harsh conditions mean that only smaller carnivorous dinosaurs could have survived in the tropics.
In order to come to this conclusion, the scientists examined rock samples taken from northern New Mexico.
According to the researchers, the rocks they analyzed had been deposited by rivers and streams more than 200 million years ago.
They were able to track the changes in the ecosystem and also estimate the levels of CO2 of that period.
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