Paleontologists have long debated the question of dinosaur metabolism: whether it was hot, like modern birds and mammals, or how the slower metabolism of modern reptiles. In a surprise, the answer seems to be both.
“Although we assumed most dinosaurs were warm-blooded, there was no way to measure basic metabolic capabilities,” said Jasmina Weimann, a paleontologist at the California Institute of Technology. In the absence of available dinosaurs, he said, paleontologists who were faced with questions about prehistoric metabolism, whether it was a warm-blooded or cold-blooded monster, for example, had to rely on indirect evidence, such as evidence isotopic. or the growth rates of the bone segments.
Now, Dr. Weiman and colleagues have devised a new method for directly measuring the metabolic rate of extinct animals. His findings, published Wednesday in Nature, stated that many dinosaurs, as well as their winged relatives, the pterosaurs, were warmer-blooded than their ancestors. But in one twist, research also indicates that some herbivorous dinosaurs spent tens of millions of years developing a cold-blooded metabolism like that of modern, ancient reptiles.
The team analyzed more than 50 extinct, modern vertebrates from the Yale Peabody Museum of Natural History collections, including mammals, lizards, birds, and 11 different non-bird dinosaurs. Through laser spectroscopy, they identified a specific molecular marker of metabolic stress in both fossils and modern bone, an indicator that correlates directly with the amount of oxygen the animal breathes. This, in turn, is a direct indication of metabolism.