Study: Humans, dogs and bats may have coexisted with dinosaurs

Scientists have spent a long time debating whether an early form of humans existed before the extinction of the non-avian dinosaurs, but a new study published June 27 may end the debate.

Peer-reviewed researchPublished in the academic journal Current BiologyUse statistical analysis of fossils to determine whether placental mammals lived before the extinction of the dinosaurs.

Fossils of placental mammals have been found in rocks dating back less than 66 million years, which coincides with the date when an asteroid hit Earth causing a mass extinction. Based on this, the researchers believe that a group of placental mammals evolved after the mass extinction. However, some fossils have been found that pre-date the asteroid, indicating that placental mammals coexisted with dinosaurs and diversified and evolved after the asteroid.

It turns out that primates, from which humans, rabbits and hares, and dogs and cats evolved, evolved just before the mass extinction, which means that the ancestors of humans co-existed with the dinosaurs. Having survived the asteroid impact, placental mammals proliferated and evolved, which may have been driven by a loss of competition from the dinosaurs.

The researchers comment on their study

We have collected thousands of fossils of placental mammals and have been able to see the patterns of origin and extinction of different groups. Based on this, we can estimate when placental mammals evolved,” researcher Emily Carlisle, from the University of Bristol’s School of Earth Sciences, said in a statement from the university.

“The model we used estimates ages of origination based on when the subspecies first appeared in the fossil record and the pattern of species diversity through time for the subspecies. Extinction ages can also be estimated based on the last appearance of when the group went extinct,” said researcher Daniele Silvestro, from the University of Fribourg.

“By examining both the origins and the extinctions, we can clearly see the impact of events such as the K-Pg mass extinction or the Paleocene-Eocene Thermal Maximum (PETM),” said researcher Professor Phil Donoghue, from the University of Bristol.