The number of mammalian skull bones has been reduced in favor of more efficient feeding. Reported by the University of Birmingham.
In many vertebrate groups, such as fish and reptiles, the skull consists of many small fused bones. A similar structure was present in the first mammals that lived about 300 million years ago. However, in the course of evolution, about 150-100 million years ago, the number of skull bones in them steadily decreased.
For a long time it was believed that this was necessary to strengthen the bite or increase the strength of the skull. Now Stefan Lautenschlager and his colleagues understand that this is due to the redistribution of mechanical stress in the bones to remove them from the brain.
“The reduction in bone number led to a redistribution of stress in the skulls of early mammals. During feeding, the scientists were diverted from the part of the skull containing the brain to the sides of the skull, which may contribute to increased brain size,” the scientists said.
The study also showed that mammals shrank in body size as the number of skull bones decreased, with some beginning to be only 10-12mm in length. This miniaturization limited available food sources and mammalian ancestors adapted to feeding on insects.
This combination of small size, reduced skull bones, and feeding on new food sources such as insects allowed the ancestors of modern mammals to thrive in the shadow of the dinosaurs.
Then, after the extinction of the dinosaurs, about 66 million years ago, this group of animals diversified and occupied empty ecological niches. As a result, some mammals became larger than the vast majority of dinosaurs.
ancient biologists approvedthat the moths’ “tails” act as decoys for bats.