The scientists already had asked to numerous times why the mammals (also the human beings) had been capable to develop bigger and complex brains that other animals, brains that in some cases had grown more up to ten times than relative the corporal size?
Now, a team of paleontólogos carried through an one study published in the Science magazine, where they creem to have discovered the reason: to facilitate a sensible sharp of the olfato. The secret meets in two miniature mammals of the beginning of the Jurássico with aspect of musaranho.
Researchers of the universities of the Texas and St Mary and the Museum Carnegie de Natural História in Pittsburgh (Pensilvânia) had used one technique of cat scan computorizada with rays X to study the rare fósseis of the skulls of two creatures, the Morganucodon and the Hadrocodium, of 190 million years of antiquity, whose remaining portions had been found in China.
The team discovered that these animals, two of the first known species of mammals, had well bigger brains that the waited one, especially to take in account its scarce corporal mass. The Hadrocodium badly weighed two grams.
The computorizada cat scan allowed the researchers to observe the interior of the skull of these animaizinhos without having that to destroy the valuable fósseis. Later, they had constructed a virtual mold of its brains, that had been compared with another dozen of fósseis and the brains of 200 species of mammals that live currently.
The results, according to scientists, had been surprising. Also it has 190 million years, the brain of the first mammals was especially great (in relation its corpora mass), with a size that if approaches to the ratios seen in the modern mammals.
After observing the three-dimensional images, the scientists had arrived at the conclusion of that the brain of the mammals evolved in three main stages: first he improved the direction of the olfato, later the tato or the sensitivity of the one for the corporal one, that he acted as a controller of the space and, finally, coordination to neuromuscular it.
Second, Zhe-Xi, one of the responsible ones for the article:
- “Our study sample clearly that the olfativa part of the brain and the entailed part to the tactile sensation through the skin if had extended in these first mammals.”