Scarf gloves, heating blankets, hot pot hot water... Various "warm artifacts" are standard in winter, but they are the supporting roles of our body". Regardless of winter or summer, our body temperature is maintained at thirty-six or seven degrees Celsius. Traveling back hundreds of millions of years, did dinosaurs maintain their body temperature the same way we did? Recently, at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, associate researcher Zhao Qi showed reporters a small box filled with dinosaur bone tissue slices, and the "thermal insulation secret" of dinosaurs is among them.
Small theropod dinosaur bone tissue slices. Photo by Xinhua News Agency reporter Zhang Xiaojie
Zhao Qi introduced that the middle section of the dinosaur limb bone is ground to a thickness of about 50 microns, and the secret can be "decoded" through the microscope. Although dinosaurs are nicknamed "big lizards" by many people, some structures in dinosaur bone tissue are unexpectedly more similar to humans than typical reptiles such as lizards and crocodiles.
Zhao Qi showed reporters the bone tissue structure diagram of dinosaurs, crocodiles and humans. "This 'small circle' we call the secondary bone unit, also called the Havreth system, there are many dense 'small circles' in the bone tissue of large dinosaurs and humans, but crocodiles do not." He explained that the Haworth system represents a higher metabolic rate. This helps researchers judge that dinosaurs are likely not to rely on "foreign aid" like crocodiles, lizards and other extratropical animals, raising body temperature through external heat, but closer to internal warm animals, such as humans, birds, etc., which are themselves "a good hand" to maintain body temperature and can maintain a stable body temperature.
The left, middle and right are crocodiles, large sauropods, and human bone tissue charts. The "small circle" in the middle and right figures is the Havals system. Photo by Zhang Xiaojie, Xinhua News Agency
Using isotopic methods, scientists estimated the body temperature of some dinosaurs. For example, titan dragons have a body temperature of 38 degrees Celsius, and oviraptors have a body temperature of 32 degrees Celsius. Zhao Qi introduced that by analyzing the fossil surrounding rock of Oviraptorosaurus, scientists confirmed that the ambient temperature at that time was about 26 degrees Celsius. "Usually, if an animal can maintain a stable body temperature of more than 5 degrees Celsius above the ambient temperature, it can be considered a typical internal temperature animal." Zhao Qi said.
With the help of body temperatures above ambient temperatures, dinosaurs achieved a series of "achievements". "For example, some small dinosaurs had the behavior of incubating eggs, which first required them to have a higher body temperature. Dinosaur fossils found in Antarctica also suggest that dinosaurs are widespread, far outpacing reptiles that are mostly distributed in tropical and subtropical regions. Zhao Qi said.
The high metabolic rate also added a different kind of "trouble" to the dinosaurs. Zhao Qi explained that in general, internal and external temperature animals of the same size and the same body temperature consume 6 to 10 times the energy of the latter. This forced the dinosaurs to spend a lot of time eating. "Some of the large plant-eating dinosaurs may have started eating from the moment they woke up." Zhao Qi said.
Whether dinosaurs are endothermic or extrapateothermic is not only about the dinosaurs themselves, but also an important aspect of scientists' study of the evolution of vertebrates. "Today's birds evolved from dinosaurs, and they evolved in two lines with mammals, including humans, but eventually both evolved endothermals. Interestingly, there are many similarities in the evolutionary processes of the two, such as the fact that they both initially achieved an increase in body temperature through megasemization, but eventually these giant animals went extinct. Zhao Qi said that the real evolution of animals in the internal temperature is the miniaturized animals. What are their "keep warm" tricks? "Small mammals are insulated by their hairs, while some small dinosaurs have feathers that are kept warm by feathers." He said.
Text reporters: Zhang Xiaojie, Zhang Quan
Video reporter: Zhang Xiaojie
Curated/Edited: Gemdale
Source: Xinhua News Agency