Why Didn't the Dinosaurs get Arthritis?

First, here's my general line of explanation I believe the dinosaur extinction may have been because they were cold blooded (endothermic) and this would be how and why they went extinct. As in my explanation precession began in the Jurassic because of the uneven torque between the N and S ocean with the continuous band of water caused by the breakup of the one continent of gondwanaland and the evidence known for the submergence of the land bridge between S SA and antarctica 87 million years ago, this would have caused seasonal winds because of the increase of the precession that would have caused the winds and colder temperatures farther north and south of the equator, the dinosaurs lived in an ever narrower band of warm tropic weather and the birds and mammals had a large N and S realm left unoccupied by the dinosaurs. When the impact hit the tropics the dinosaurs had the bad luck of already being weakened and the luck that the impact hit the tropics. (The other reptiles like the snakes and lizards didn't go extinct would be because they were on the other side of the world.) Thus the rise of the birds and mammals and the extinction of the dinosaurs would be explained by essentially the idea that the dinosaurs were endotherms.

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The dinosaurs were by far the largest land animal and the weather before the precession was good and constant for millions of years in their evolution. The earth was spinning faster and the precession and it's seasonal change that would have stressed the dinosaurs wasn't yet involved, so the sun may have been burning warmer as I say on this site, there would have been constant good weather for millions of years as in the times between the ice ages which are of much shorter duration than the times like the mesozoic.

The constant warm weather and it's even temperature because the earth was spinning faster with not much seasonal weather change would explain how the dinosaurs are found to have been living not just in the tropics but also the arctic and antarctic too. The warm and even temperatures would have made the dinosaurs endothermic because for more giant size which evolution would have favored, if the dinosaurs were actually exotherms they would have generated far too much heat to live. Giants like the herbivores if exotherms would have had to eat so much they couldn't have stayed alive because they would have had larger need of food to maintain the inner fire. The small mouth of the brachiosaurus and brontosaurs would have been because they both didn't have to eat a lot and they had no way to eat a lot. Most of the body mass they added they would have kept. The dinosaurs giant size would be because it was an advantage in evolution, a large animal fears no predators, an elephant just sits on their competitors! When there's more food available like in our own evolution larger size and height soon follows. The dinosaurs unlike mammals and reptiles today were in a constant sea of good weather and the food was available "year round". The weather was good for millions of years and each night there wasn't so much heat stress, or the seasonal lack of food and stress of winter. Even so the easy availability of food and the need to stay endothermic once they evolved in the heat both would have slowed down the dinosaurs and it would have been easier to go slow, that is to not have as much of an evolutionary acceleration as the warm blooded life has. The external temperature was nonetheless stressful for a more giant dinosaur because the core body temperature would have been more constant and cool and the outer temperature would fall and rise in the 24 hours. Reptiles in the desert today overheat later in the day and burrow to stay cool, they have to spend a large portion of their day either in the sun to stay warm or burrowing to moderate the heat. This would have taken up most of the dinosaur's time with less time to play or evolve big brains since the solution to find heat or cool was simple and didn't take much of the web sites to solve. With the large body mass of the giant dinosaurs even a small change in the outside air temperature would have been stressful because of more metabolic power needed to compensate. A larger dinosaur would have more to make up for, Thus though being an endotherm would have allowed the dinosaurs giant size, at even larger size it might also have been a limit too.

Many things are thus explained by the dinosaurs being endothermic, their small brain size because of easy to reach food and no tendency to speed up beyond a certain level due to the metabolic stress, and how the comet impact was fatal to them and not the mammals and birds.

As I say elsewhere my definition of endotherm is a functional one, an animal that can't live in the cold weather is by definition and endotherm. This definition is general enough to define endotherm in a reliable enough way to those who say there is no real definition for endotherm or exotherms because the physiology of life is too complex.

That the dinosaurs have been found to have not gotten arthritis could also be because of the slower metabolism constant higher heat would have caused. If the fastest and animal like allosaurus could run just 35 mph and was limited by the air temperature, and all the other dinosaurs had the same limit, neither would the herbivores have to run faster from them, so even if the weight on their bones was great the dinosaurs would have had reduced scraping on without so much running and if their metabolism was generally slow their immune system would have had reduced volatility. Though the top speed was 35 miles per hour the average speed may have been slow! much slower than life like mammals today. Higher speed evolution is also more unpredictable, so our own warm blooded evolution would have more risk of errors like attacking our own tissues as in autoimmune illness like arthritis. Thus as the dinosaurs were more slowly evolving to giant size evolution would have proofread and corrected autoimmune illness more accurately so the dinosaurs wouldn't have had this limit and this seems to predict that the dinosaurs would have had fewer immune problems than other life like the birds or mammals if we can find proof of this like in the dinosaur fossils with DNA.

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This seems to be more evidence that the dinosaurs were endothermic because of slower evolution both in running and the speed of the evolution of the changes in their metabolism. And it also tells us the obvious reason for lo impact aerobics being better to reduce the risk of arthritis, even so we might also look at our older evolution to see when we first started to evolve arthritis and then try to undo out DNA from that time so arthritis would be cured for us too.