In 1964, the American paleontologist John Ostrom discovered Deinonychus antirrhopus. Dinosaurs are about three meters long, which is not surprising among dinosaurs, but it has rewritten the image of dinosaurs in people's minds. The tail of dinosaurs was joined by bone processes and ossified tendons, and it was straight and stiff. Sitting on a stick is obviously impossible. This tail is not suitable for supporting weight, and it is much more suitable if it is used as a balance bar for acrobats. On the two hind legs of the dinosaur, each with a large hook claw, it must raise one foot to stab the prey with this weapon, and the tail that maintains a balance can be of great use.
(Dinosaur preys on Diplodocus.) Image from the web)
Like Kepp a hundred years ago, Ostrom was fascinated by ferocious carnivorous dinosaurs. Dinosaurs are agile and can be called the assassins of dinosaurs. However, moving fast requires capital. Modern reptiles are cold-blooded, and compared with warm-blooded animals, cold-blooded animals have a very slow metabolism, consume slow energy (a lizard needs less than one-tenth of the food of the same weight), and slow muscle movements. "Horsepower" is insufficient, and it is impossible to jump up and down like a dinosaur. As mentioned earlier, sauropods are straight on all fours and walk on land, and although these behemoths move slowly, they also need a huge amount of energy to support their weight. The power of cold-blooded animals is not enough.
(Lizards that have long been considered "cousins" of dinosaurs.) Image from the web)
Cold-blooded animals like to bask in the sun, the body is warm, the biochemical reaction in the body is accelerated, the metabolism is accelerated, and the strength will increase. Did dinosaurs use solar energy to "fuel" themselves? In 1946, at the American Museum of Natural History, paleontologist Edvvin Colbert and his colleagues decided to do a "simulated field" experiment. They chose hot Florida as the experimental site, and there were no "real" dinosaurs, so they took alligators weighing 1 to 22 kilograms instead. Let them bask in the sun, and then take the temperature of the alligators. Colbert even considered that some dinosaurs stood on two feet, so the unlucky crocodile was propped up by a wooden shelf and posed upright.
(Alligator basking in the sun.) Image from the web)
The smallest crocodile, the body temperature rises five times faster than that of the larger (14 kg) crocodile. It can be inferred from this that dinosaurs, which are 700 times heavier than experimental crocodiles, had a body temperature increase of one degree Fahrenheit and had to bask in the sun for 86 hours! An unfortunate accident occurred during the experiment: two alligators died of skin sunburn. When wild alligators feel that their epidermis is too hot, they can jump into the water to cool down, and the experimental crocodiles are chained up and have nowhere to escape. Dinosaurs rely on the sun to heat up, the depths of the body have not yet been heated, the skin is probably already brittle. Ostrom, along with his proud student, Buck, who studied elephants and dinosaur feet, threw a brilliant conclusion. Dinosaurs should be warm-blooded animals!
(Image from the Internet)
In addition to the nimble dinosaurs and the hapless crocodiles, they cite a lot of evidence. For example, Buck mentioned that there are very few fossils of carnivorous dinosaurs. Where a large number of fossils are buried, the number of carnivorous dinosaurs is roughly equivalent to 3%-5% of vegetarian dinosaurs. This huge number difference is closer to today's ferocious birds and beasts of prey (warm blood) than to reptiles (cold blood). It takes many herbivorous dinosaurs to "feed" a carnivorous dinosaur, indicating that carnivorous dinosaurs were very capable of eating. Only warm-blooded animals with rapid metabolism need so much food.
The difference between the words "warm" and "cold" implies a huge change in the paleontological community. Dinosaurs are not bulky, sluggish lizards, but powerful, athletic, hot-blooded animals that were once mired in a quagmire and now have footprints all over the continent. Buck proudly named his article "Dinosaur Renaissance." After a revolution, dinosaurs, like the Renaissance, became more lively, more vivid, and more colorful.
(Excerpt from Antelope and Bee: An Evolutionary Wonder of Beings)