Why are Tyrannosaurus rex short-handed? The real reason is kind of funny

  In the face of a Tyrannosaurus rex model, I believe many people will blurt out: “Your hands are so short.”
  Why are Tyrannosaurus rex short-handed? A new study published in the “Polish Journal of Paleontology” offers a hilarious and distressing explanation…
  Kevin Padian, a paleontologist at the University of California, Berkeley, has been brooding recently because many students have asked him the above question .
  For example, a 14-meter Tyrannosaurus rex might have a 1.5-meter-long skull, but an arm bone less than 1 meter long—equivalent to a 1-meter-eight human male with 13-centimeter hands. Moreover, a big head with short hands is somewhat out of place.
  Facing questions from students, Padian often starts by throwing out a series of hypotheses put forward by paleontologists. For example, the short arms of Tyrannosaurus rex may have acted as “chest buckles” during mating, which were used to fix the mate in a special position for easy action; or, because they lay on the ground to rest, their forelimbs could help them prop up their upper bodies and stand up faster. ; Or, when the enemy is unprepared, push him down.
  But every now and then, his students are still staring at the life-size replica of the Tyrannosaurus Rex with suspicion. Even Padian himself thought the speculation seemed too unconvincing. First of all, the short arms of Tyrannosaurus rex can’t encircle the object at all, it is difficult to give each other a “love hug”, and the strength is not enough to control it; as a weapon, the function of the short hand is not strong, and its power is far less powerful. jaw and teeth.
  However, the predecessors who belonged to the Tyrannosaurus family obviously had longer and stronger “arms”, so the evolution of Tyrannosaurus Rex’s “shorter hands” must have its own secrets. Padian decided to find out for himself.
  After reviewing many documents and investigating archaeological records, Padian came to a new conclusion that made people laugh and cry: The reason why Tyrannosaurus rex was short-handed may be that it was afraid of being bitten while eating.
  In recent years, a growing body of fossil evidence suggests that Tyrannosaurus rex may have lived in packs — they hunted together and shared food. But at the same time, Kong Wu’s powerful arm has become a safety hazard.
  Just imagine, “several dinosaurs gathered for a meal, scrambled to tear and gnaw at the bones of their prey, and each had a huge head, powerful jaw, and sharp teeth.” Padian said, then, if If the hand is stretched too long, it is likely to be accidentally eaten or injured by the gobbling dinosaur friends.
  ”And, if your fellow dinosaurs think you’re getting too close, they will instinctively gnaw your arm as a warning!” This behavior has precedents in other animals with powerful bites, such as Cuomo Duolong and crocodile often lead to “blood cases” because of eating.
  The bite force of Tyrannosaurus rex is almost 10 times that of modern alligators. Once injured, it will cause severe infection, bleeding, and even fatal. Since it is enough to prey with the lower jaw, the arm becomes a burden. Because of this, the Tyrannosaurus rex’s hands became shorter step by step, and finally ended up with “uncoordinated limbs”.
  So, stop laughing at Tyrannosaurus Rex for being short-handed, this is actually the survival wisdom of the ancient overlords!+

  Some studies have found that species that grow and metabolize quickly also typically have shorter lifespans; but in others, the link between metabolic rate and lifespan is less clear. A study by John Speckman’s team at Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences clarified the impact of metabolic rate and body temperature on lifespan, revealing that body temperature has a greater impact on lifespan under certain conditions. The research results were recently published in the journal Nature Metabolism. The researchers placed mice and hamsters in a higher temperature environment (32.5 ° C), the body temperature of these animals increased, and the body’s metabolic rate was maintained at a low level to reduce heat production and avoid hyperthermia. Both animals experienced accelerated aging and significantly shorter lifespans.
  The study then exposed the two animals to breeze conditions. This change did not significantly affect metabolic rate, but increased thermal conductivity, promoted body heat dissipation, and lowered body temperature. Both animals delayed aging and extended lifespan. This reverses the adverse effect of high temperature on life.
  Based on this experiment, the researchers believe that body temperature may have a greater impact on lifespan than metabolic rate, and lowering body temperature is conducive to delaying aging and prolonging lifespan.

  According to an animal behavior study published on March 31 in “Scientific Reports”, a subsidiary of Nature Research, zebra-like cichlids (a type of cichlid) and formula fish can complete calculations within 1 to 5 plus or minus 1 digit. Scientists believe that the results show that fish’s arithmetic abilities are comparable to those of other vertebrates and invertebrates.
  Vera Schrousel, a researcher at the University of Bonn in Germany, and her colleagues tested whether eight zebra-like cichlids and eight pearl formula fish could be trained to remember that blue means plus 1, and yellow means minus 1 bit. The researchers first showed the fish cards with blue or yellow graphics, and then gave them two doors with different numbers of graphics on the cards, one of which was the correct answer. For example, if a fish is first shown a card with 3 blue shapes, they will add 1 to the 3 and swim through a door with 4 shapes on the card. The fish that swim through the correct doorway are rewarded.
  The researchers found that six zebra-like cichlid and three formula fish were trained to remember the relationship between blue and addition and yellow and subtraction. On average, zebra-like cichlids remembered these relationships after 28 rounds and formula fish after 68 rounds. Fish generally performed well on these types of tasks, but addition was learned faster than subtraction, and zebra-like cichlids had slightly greater individual differences than formula fish. In the addition task, the zebra-like cichlid got it right 296 times (78%) out of 381 tests, and the formula fish got it right 169 times (94%) out of 180 tests. In the subtraction task, the zebra-like cichlid got it right 264 times (69%) out of 381 tests, and the formulafish got it right 161 times (89%) out of 180 tests.
  While the research team speculates that computing power may not be particularly important for either species, they believe it could help the two species identify other individuals by appearance, such as counting stripes or spots on a fish’s body. The researchers point out that this result suggests that there is a need to re-study the cognitive abilities and perception of fish.