先说一下极地恐龙的观点。当恐龙存在的时候,极地,也就是这些发现化石的地方比现在要暖和很多。而且当极地很冷的几个月里,这些极地恐龙会迁徙到暖和的地方或者像现在爬行动物一样选择冬眠。所以,在极地发现恐龙化石不能证明恐龙是恒温动物。
Well, what about the fact those dinosaurs have their legs placed under their bodies, not out to the side like crocodiles. That doesnt necessarily mean dinosaurs were high-energy endotherms built for running. There is another explanation for having legs under the body. This body structure supports more weight, so with the legs under their bodies, dinosaurs can grow to a very large size. Being large had advantages for dinosaurs, so we dont need the idea of endothermy and running to explain why dinosaurs evolved to have their legs under their bodies.
那么,恐龙的腿在身体下方而不是两侧是怎么回事呢?这个是不足以证明恐龙是可以进行奔跑类剧烈运动的恒温动物。腿生长在身体下部对于恐龙是别有的意义的。这样的结构可以支撑更多的重量。所以腿长在身体下部可以让恐龙长到非常大。对于恐龙来说,巨大的重量是非常有意义的,所以没有比用要用恒温动物和奔跑来解释为什么恐龙进化出这样的身体结构的。
Ok, so how about bone structure? Many dinosaur bones do have Haversian canals, and that is true. The dinosaur bones also have growth rings. Growth rings are thickening of the bone that indicates periods of time when the dinosaurs werent rapidly growing. These growth rings are evidence that dinosaurs stopped growing or grew more slowly during cooler periods. This pattern of periodic growth, you know, rapid growth followed by no growth or slow growth, and then rapid growth again, is characteristic of animals that are not endotherms. Animals that maintain a constant body temperature year-round as true endotherms do grow rapidly even when the environment becomes cool.
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