No, we don’t just mean that we all have some nasty folks in our family tree–We’re talking about an actual rat-like mammal that is the common ancestor of all humans. It weighed about half a pound, had a long furry tail and ate insects (something WE may do more of in the future).
This ancestor emerged within 200,000 to 400,000 years after the dinosaurs died off. However, it took millions of years before the first members of this modern mammal appeared in great numbers. A research team used a combination of fossil evidence and genetic data encoded in DNA to determine the ancestor’s status.