According to scientists, dinosaurs wrong chewed.
The ancestors of mammals are able to chew, that is the best dinosaur used fetched them food, helped them survive the asteroid and volcanic winter.
David Grossnickle (David M. Grossnickle) from the University of Chicago (USA) put forward the hypothesis that the survival of mammals during the dinosaur extinction was due to the ability to chew by moving their jaws in a horizontal plane and thereby thoroughly grinding your food. The corresponding article was published in Scientific Reports.
The author constructed a three-dimensional model of the teeth and jaws of early mammals that lived in the Cretaceous period. He was able to show that in parallel with the development of the teeth and recesses of the pits in the gums under them, these animals have developed muscles, fastened to the jaws. This, says the scientist, giving them the opportunity to vigorously chewing, moving the jaw in a horizontal plane. Such a skill is very important for pre-crushing of food, it allows it to better absorb.
66 million years ago the Earth was struck a blow Chekalovskoe asteroid with a diameter of 10 kilometers. Its burst strength was equal to 100 million megatons, that is was much more powerful than the entire nuclear Arsenal of mankind. On the planet for years reigned the so-called asteroid winter. The plants have stopped actively photosynthesize food for the animals was quite small. In such conditions, said Grossnickle, even a moderate advantage in the structure of the system of chopping the food could have serious implications for the survival of a species.
At the same time the point of view of the researcher may cause objections from other research groups. The fact that actually it is not clear whether any dinosaurs could not chew. Hadrosaurs not so long ago was found a kind of bony hinge, giving them the mobility of the upper jaw (and the mammalian movable bottom only). It is expected that thanks to this hinge, the jaws of the hadrosaurs could move in the horizontal plane. In the back of their beak, similar to a very big duck, was flat teeth, technically gadelshina for thorough grinding of food. However, hadrosaurs, and other dinosaurs (except Gladkochub ancestors of birds), did not survive the fall Chekalovskoe of the asteroid and went extinct in the late Cretaceous.
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