A new research from the University of Bristol provides evidence that many mammals were already turning towards a more terrestrial lifestyle that leads to the collective collective extinction that eliminated the inaccurate dinosaurs 66 million years ago.
DryThe late Jorani relatives of the mammals of the Cretaceous period. Credit image: James Brown / Pamela Jill / Bristol University.
Current mammals live in a variety of dominant habitats dominated by flowering plants (vascular cassette).
Unlike those provided by the vertical vegetation, the habitats of forests and forests have dense and complex trees as well as larger trees, providing high biological diversity and resources for land mammals of all sizes.
However, these habitats dominated by flowering plants are relatively new in Earth’s history, as they are mainly an advantage in the era of Cenozoic (66 million years ago until today), but they are first developing at the end of the Cretaceous period.
“The medium mammals were almost small, with less than 5 kilograms of the mass, with the largest number of about 10 kg,” said Professor of Bristol Crystin Janes and her colleagues.
“In fact, most mammals today are small, with medium body mass about 0.5 kg, but in Cenozoic a variety of large mammals have evolved.”
“The size of the small size of mammals of intermediate mammals is often attributed to the suppression of dinosaurs, but recently, the late Cloen radiation of the blood vessels, and the plant habitats that it provides, have been probably more important than the dinosaurs in explaining the patterns of the intermediate intermediate mammals development.”
“What is the preference of the pillar of these mammals, tree or ground, and is this change at the end of the Cretaceous era with a change of vascular habitats?”
In their research, the authors analyzed the small bone fragments, specifically from the bones of the extremities, from the ancient mammals (Merikha and shameful mammals) located in Western North America, the only place that carries the well -preserved ground fossil records of this time.
They discovered signs that these mammals were adapting to life on Earth.
The ends of the bones of the limbs have been analyzed because they carry signatures of the kinetic habit that can be statistically compared to modern mammals.
“It was already known that the vegetarian life changed at the end of the Cretaceous period, with flowering plants, known as blood vessels, creating more diverse habitats on Earth.”
“We also knew that the mammals that inhabit the trees are struggling after the effect of the asteroid.”
“What is not documented, is whether mammals have become more earthly, in line with habitat changes.”
While previous studies used the full skeletons to study the movement of old mammals, this research is one of the first to use small bone elements to track changes within an entire society.
Professor Janes said: “Plant habitats were more important in the path of the development of chalk mammals more than any impact of dinosaurs.”
“We have known for a long time that the long bone joint surfaces of mammals can carry good information about their position in movement, but I think this is the first study that uses these small bone elements to study change within society, rather than just individual types.”
the Ticket It was published in the March 2025 issue of the magazine Cases.
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Christine M. Janis And others. 2025. On Earth: My breasts have become the most earth at the end of the Cretaceous era. Cases 68 (2): E70004; DOI: 10.1111/pal.70004