Dinosaur bone almost always has well-developed fibrolamellar bone

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The critical point is that fast growth requires a fast intake of food, and, in wild juveniles, fast food intake requires greater activity. Walking dinosaur costume In small youngsters, only heightened metabolic rates can drive such activity, rates at least at the tenrec level. Relistic dinosaur costume Because of this, only endotherms grow rapidly and develop substantial fibrolamellar bone in the wild. No known ectotherm can do this. As you mlght suspect by now, dinosaur bone almost always has well-developed fibrolamellar bone, firm evidence that they grew rapidly in the avian-mammalian manner. This seems to be confirmed by another aspect of bone histology, growth rings. Formed each year as winter or the dry season slows growth, these are corrunon in reptiles, even the tropical ones. Some temperate and polar birds and mammals have similar rings in their long bones, but as far as I know such rings are entirely absent in living tropical ones. It is hard to tell if the birds’ rings are real growth marks, and it has been found that more than one forms each year.r. Dinosaur costume In any case, such “growth” rings occur in onry a few big theropods. when they do show up they are rather low in number. They are not the many dozens of very thin bands crowded into the bones’outer layers that should be expected if these were longmaturing ectotherms. Considering that each ring forms at least once a year, if not more rapidly we deduce that their owners were growing to large sizes in only a few years. So small theropods matured in about ayear, and were ord in a few. The giants were adults in a decade or two, and reached perhaps sixty or so years in age. Speculations that big theropods lived for centuries are not supported by the data.