Mice had wandered on Earth millions of years ago with dinosaurs

The rodent called Jeholbaatar kielanaeis is part of a mammal species that survived the onslaught of an asteroid that ended the dinosaur era on Earth.

A fossil mouse that can run around with dinosaurs has been discovered in Cretaceous rocks in northeast China.

This creature is about the size of a hamster with ruffled fur but has a special esper power that is incredible hearing. This may help it avoid the dinosaurs moving quickly during that period.

Image depicting ancient rats.

"Based on the shape of the lower cheek, Jeholbaatar has an omnivorous diet like worms, arthropods and plants. It has a different jaw movement while chewing," researcher Yuanqing Wang from the Institute of Paleontology. Vertebrate and ancient Chinese anthropologist in Beijing said.

Jeholbaatar's spectacularly well preserved skeleton is almost complete and even includes its upper and lower teeth.

The fossils were dug up at a famous animal graveyard called the Jiufotang Formation in Liaoning Province.

Commonly known as Jehol biota , the animals found there include feathered dinosaurs, first mammals, birds, fish and insects. Jeholbaatar may be a big part of a small dinosaur's diet. Although it looks a lot like a modern mouse, it is actually part of a separate evolutionary or mammal branch. In fact, they have a fossil history of 100 million years, the longest among mammals.

Due to the well preserved nature of the left middle ear bone, the specimen shows a unique configuration with more complete components than before.

These mammals evolved with dinosaurs because they adapted to eating flowering plants, or angiosperms, that began to appear 140 million years ago. They even survived the asteroid attack that wiped out the giant reptile 65 million years ago and continued growing after that.

They eventually disappeared from Earth some 34 million years ago after losing to other mammals such as primates, ungulates and rodents.

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