Dinosaurs, the largest creatures that ever roamed the Earth millions of years ago, may have had warm blood like mammals and birds, not cold like reptiles.
The new study was conducted by Michael D’Emic, paleontologist at the Stony Brook University in New York.
He came to the conclusion that dinosaurs may have had warm blood after analyzing their body mass and growth rates found in fossils like that of the infamous T-rex.
D’Emic disagrees with previous research which suggests that dinosaurs were neither warm-blooded nor cold-blooded creatures, but somewhere in between the two.
Researchers have debated for a very long time whether dinosaurs had cold blood, which made them slow and lumbering creatures, as it was previously believed, or they were warm-blooded, which allowed them to lead a more vigorous, active lifestyle.
D’Emic said in his paper that the point of his study was to prove that dinosaurs that have been found so far were warm-blooded creatures just like mammals are today.
The researcher argued that a previous study from 2014 which suggested that dinosaur were both cold and warm-blooded did not analyze the prehistoric animals statistically within the same group as modern birds.
The researcher added that the previous study underestimated the growth rates of the dinosaurs.
Modern birds evolved from small feathered dinosaurs approximately 150 million years ago, and since modern birds have warm blood, it’s plausible that dinosaurs were warm-blooded as well.
The scientists who conducted the 2014 study analyzed the metabolism of 21 species of dinosaur using a formula based on the animals’ body mass.
The dinosaurs’ body mass was revealed by the bulk of the thigh bone and the growth rates. These were indicated by the growth rings found in the fossils, similar to the rings found in tree trunks.
The analyzed dinosaur species included long-necked dinosaurs, predators like Tyrannosaur rex and plant eating dinosaurs.
They compared the data with that of modern reptiles, fish, birds and mammals.
But D’Emic reexamined the same data and concluded that dinosaurs were actually warm-blooded creatures.
The paleontologist detailed his findings in the journal Science.
However, the authors of the previous study do not agree with D’Emic conclusions saying that their initial findings still stand.
John Grady, biologist at the University of New Mexico and one of the researchers involved in the previous study, said that:
“Comparing dinosaur growth with the observed growth rate of living vertebrates clearly shows that non-avian dinosaurs were mesotherms.”
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