Mammals adapted from life to trees to live on the ground before asteroid killing dinosaurs, research reveals

More mammals lived on the ground several million years before the mass extinction event which destroyed the dinosaurs, revealed new research carried out by the University of Bristol.

The study, published in the journal PaleontologyProvides new evidence that many mammals were already moving to a lifestyle more on the ground leading to the impact of the asteroid.

By analyzing the fragments of bone with small fossilized, in particular the end of the bones of the members, marsupial and placental mammals found in the west of North America – the only place with a well -preserved terrestrial fossil file from that moment – the team discovered signs that these mammals adapted to life on the ground. The end of the bones of the members has been analyzed because they wear signatures usually Locomotoire which can be statistically compared to modern mammals.

The main author, Professor Christine Janis, of the Earth Sciences School of the University of Bristol, said: “It was already known that plant life had changed towards the end of the Cretaceous, with flower plants, called angiosperms, creating more diverse habitats on the ground.

“We also knew that the mammals living in trees had trouble after the impact of asteroids. What had not been documented was whether the mammals became more terrestrial, in accordance with the habitat changes.”

While previous studies have used complete skeletons to study the movement of old mammals, this research is one of the first to use small bone elements to follow changes within an entire community. The team used statistical data from museum collections in New York, California and Calgary to analyze these tiny fossil.

Professor Janis added: “Vegetable habitat was more important for the evolution of mammals of Cretaceous than any influence of dinosaurs.”

The evidence was collected from the bone joint fragments of the Thériens mammals, which includes marsupial and placental. The team’s methods were not applied to lower mammals such as the multitberculates, which were common at the time, because their bones were different.

Professor Janis said: “We have long known that the long bone articular surfaces of mammals can transport good information on their mode of locomotion, but I think that this is the first study to use such small bone elements to study the change within a community, rather than individual species.”

Although this research marks the end of the project, the results offer new perspectives on the way in which prehistoric mammals have reacted to changing environments – a few million years before the impact of asteroids overlooks life on earth.