アメリカ自然史博物館のインスタグラム(amnh) - 8月1日 07時53分

Troodon formosus, thought to be among the most intelligent dinosaurs, may provide a link between crocodilians and birds. The carnivorous Troodon grew to about eight feet long and lived about 75 million years ago during the Late Cretaceous period. Their brooding habits in particular offer clues to their position on the evolutionary chain. Troodon produced a pair of eggs at periodic intervals, maintained nests, and warmed their unhatched offspring with body heat. In 2013, scientists in the U.S. and Canada studied the porosity of Troodon eggs and compared them to eggs hatched by crocodiles and birds. An egg’s porosity helps scientists determine how much water and air can permeate the shell, and points to whether or not the parent might bury it. For eggs to survive underground, they must be more porous to ward off suffocation, as in the case of crocodilian eggs. To survive in open air, they must be relatively sealed off, as are bird eggs. Varied porosity in Troodon eggs indicates that these dinosaurs laid their eggs semi-vertically in sand and mud, always leaving a portion exposed to the air, and suggests a kind of transitory egg laying strategy that bridges the lineages of say, the american alligator and the Blue Jay. #dinosaur #dinosaurs #cretaceous #amnh #naturalhistory #alligator #allogators #crocodile #crocodilea #eggs #troodon

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