66 million years ago, an ancient animal was the ancestor of all placental mammals. At that time, an asteroid hit Earth and caused most dinosaurs to go extinct.
An old family member of humans, dogs, and bats lived with dinosaurs . It happened before an asteroid hit Earth 66 million years ago. The climate changed because of gases from the impact. This made non-avian dinosaurs disappear and caused 75% of life on Earth to vanish. This event is called Cretaceous-Paleogene mass extinction.
When the dinosaurs died, smaller animals like primates and humans appeared. The event was significant for Earth. It allowed mammals to take over habitats once ruled by dinosaurs.
Debate resolved
Scientists are looking for proof of placental animals with dinosaurs. Researchers from Bristol and Freiburg found evidence that they did exist together. They used fossils of thousands of placental mammals to conclude this fact after studying them. Placental mammals are the primitive ancestors of mammals.
Recent studies show that placental mammals, along with dinosaurs, have existed for a long time. Molecular clock data obtained from the fossil record support this claim. Early mammals lived alongside dinosaurs for a while before they died out in the Cretaceous period.
Dissecting the fossil record
Researchers gathered fossil data from placental mammals, dating back 66 million years ago. They wanted to know where these mammals came from. Emily Carlisle, co-author of the study in Current Biology, explained that they collected many fossils. From the fossils, they could see how different groups of placental mammals evolved and disappeared over time.
We can estimate the evolution of placental mammals. Daniele Silvestro, a paleo biologist at the University of Freiburg, used a model for this. The model considers when lineages first appear in the fossil record and species diversity over time. He is also a co-author of this work.
Research shows that in the Cretaceous period, animals such as primates, rabbits, dogs and cats evolved prior to mass extinction. This means our ancestors were alive then.
The researchers made a remarkable comment..
The story continues as research reveals that placental mammals did well after an asteroid hit, causing dinosaurs to die. This means that without the dinosaurs, mammals could grow and do better.
The dinosaurs died because a big rock hit the Earth. If that didn’t happen, the world would be different now.
What were those ancestors like?
We do not know how our mammal ancestors looked like. The earliest fossil evidence of placental mammals is small. An example is Purgatories, an early primate ancestor that looked like a burrowing tree-shrew. Experts suggest that our ancestors were probably small squirrels.
