Humans DID live with dinosaurs, scientists say

Our ancestors mingled with dinosaurs shortly before they went extinct, according to a new study.

Debate has long raged among researchers about when placental mammals — the group that includes humans, dogs and bats — first emerged.

Some believe they co-existed with the dinosaurs before an asteroid hit Earth and caused catastrophic destruction, while others argue they didn’t evolve until after the dinosaurs were wiped out.

Now, an in-depth analysis of the fossil record finally provides the answer: that our ancestors lived alongside dinosaurs for a short time before the reptiles became extinct.

So far, fossils of placental mammals have only been found in rocks younger than 66 million years old, when the asteroid hit Earth.

The colossal event wiped out all dinosaurs except birds and other smaller animals such as lizards and frogs.

In a new paper published in the journal Current Biology, a team of paleobiologists used statistical analysis of the fossil record to determine that placental mammals arose before the mass extinction, meaning they coexisted with dinosaurs for a short time.

Primates, the group that includes the human lineage, as well as Lagomorpha – rabbits and hares – and Carnivora – dogs and cats – were found to have evolved just before the mass extinction, meaning our ancestors mixed with dinosaurs.

After surviving the asteroid impact, placental mammals diversified rapidly, perhaps spurred on by the dinosaurs’ loss of competition, the researchers said.

Lead author Emily Carlisle from Bristol’s School of Earth Sciences said: ‘We collected thousands of fossils of placental mammals and were able to see the patterns of emergence and extinction of the different groups.

‘Based on this, we were able to estimate when placental mammals evolved.

“Unfortunately, we don’t know what our placental mammal ancestors looked like at the time.

“Many of the earliest fossils of placental mammals are quite small creatures like Purgatorius – an early ancestor of primates – a small burrowing creature that looked a bit like a tree shrew.

“So it’s likely that many of our ancestors were short and squirrel-like.”

Co-author Daniele Silvestro, from the University of Friborg, explained: ‘The model we used estimates the ages of formation based on when lineages first appear in the fossil record and the pattern of species diversity over time for the lineage.’