Warming climate could have prompted ecological changes, leading some species to develop a faster metabolism — a trait shared by modern day birds and mammals
The unique trait of warm bloodedness developed in theropods like Velociraptor, who are the ancestors of modern day birds. Photo: iStock
New research has suggested a surprising link between climate change and a key feature of dinosaurs — their ability to be warm blooded. The study, published in journal Current Biology, indicated that dinosaurs living 180 million years ago may have evolved the ability to regulate their body temperature in response to a shifting climate.
This discovery sheds light on the adaptability of these prehistoric giants and hints at the possible origin for the warm-bloodedness seen in birds, the modern-day descendants of a group of meat-eating dinosaurs called theropods, such as Tyrannosaurus rex and Velociraptor.
“We suggest that endothermy (maintenance of a relatively constant internal body temperature) might have first evolved in dinosaurs around that time (180 million years ago),” Alfio Alessandro Chiarenza, of UCL Earth Sciences and the author of the new paper, told Down To Earth.
Chiarenza and his team used dinosaurs as a case study to study evolution, particularly in response to climate change.
So, they studied the spread of dinosaurs across different climates throughout the Mesozoic Era (also known as the time of the dinosaur). This era lasted from 230 to 66 million years ago.
Some 1,000 fossils, the geography of the period, and the dinosaurs’ evolutionary trees were analysed. They also used climate models for the study.
Their study proposed that the characteristic emerged around the Jenkyns event, a period marked by severe global climate conditions of intense warmth and ocean acidification approximately 183 million years ago.
During this era, two out of the three primary categories of dinosaurs, namely theropods and ornithischians (which encompass relatives of herbivorous dinosaurs like Stegosaurus and Triceratops), migrated to cooler regions during the Early Jurassic period. The scientists speculate that these large creatures may have acquired the ability for internal heat production (endothermy) during this period.
“The environmental crisis caused by that warming might have triggered some ecological process for which some species had to evolve a more active metabolism, hence ‘warm-bloodedness’,” the author noted. These creatures were likely highly active and were able to develop, grow faster and produce more offsprings.
The researchers think that the birds’ unique ability to regulate temperature may have come from the Early Jurassic epoch as they evolved from theropods. Mammals, too, are endotherms or warm-blooded.
Meanwhile, the third group of dinosaurs, sauropods like Brontosaurus and Diplodocus, remained in warmer regions.
Chiarenza suggested that the cold-blooded dinosaurs might have grown to massive proportions and become more dependent on warmer climates as a result.
The researchers stressed that this was also an an environmental adaptation. Larger animals, with a lower surface area to volume ratio, lose heat more slowly, enabling them to remain active for extended periods.
The team now plans to investigate fossil layers closer to these periods of environmental change, which may have influenced the development of cold or warm-bloodedness.
They also aim to broaden their analysis to include more species, possibly refining analytical methods to study the data and extend research into mammals that evolved “warm-bloodedness”.
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