Prehistoric beavers paved the way for mammals in wake of dinos' departure

For a time, prehistoric beavers were the largest animals on Earth.

By Brooks Hays
An artistic representation of what the ancient beaver may have looked like. Photo by University of Nebraska, Lincoln
1 of 3 | An artistic representation of what the ancient beaver may have looked like. Photo by University of Nebraska, Lincoln

SAN JUAN, N.M., Oct. 5 (UPI) -- In millennia following the departure of the dinosaurs -- brought on by a combination of asteroids, earthquakes and massive lava flows -- one creature was able to weather the storm.

According to a new study published in the journal Zoological, a small beaver-like rodent (Kimbetopsalis simmonsae) was one of the first species to fill the ecological void left by the dinosaurs' extinction.


The newly discovered K. simmonsae fossil, unearthed by paleontologists in New Mexico, is helping scientists better understand the geologic gap between the fall of dinos and the rise of mammals known as the Cretaceous-Tertiary (K-T) boundary.

The prehistoric beaver and his relatives, part of a group called multituberculates, made their first appearance 100 million years ago, living alongside the dinosaurs. Researchers say the creatures flourished in the absence of dinosaurs, but died our 35 million years ago, replaced by modern rodents.

"We could think of Kimbetopsalis as a primeval beaver, which lived only a few hundred thousand years after the asteroid impact that killed the dinosaurs," study co-author Steve Brusatte, a researcher at University of Edinburgh, said in a press release. "The asteroid caused apocalyptic environmental change, but it seems like mammals began to recover pretty quickly afterwards."


Their beaver's teeth -- accented by sharp incisors and molars with lots of cusps -- helped it eat a variety of vegetation. For a brief period of time, after dinosaurs left the stage 66 million years ago, these prehistoric beavers and their rodent-like relatives were the largest animals on earth. Most measured no more than three feet in length.

"It's interesting that this odd, now extinct group, was among the few to survive the mass extinction and thrive in the aftermath," commented Thomas Williamson, a researcher with the New Mexico Museum of Natural History and Science. "It may be because they were among the few mammals that were already well-suited to eating plants when the extinction came."

Ancient rodents weren't the only animals to flourish in the wake of the dinosaurs' extinction, just some of the earliest. As the climate returned to normal, hoofed animals, marsupials, bats and early primates began to appear in the geologic period known as the Palaeogene.

The fossil's discovery and analysis involved the collaboration of scientists from New Mexico, the University of Nebraska and the University of Edinburgh, in Scotland.

Latest Headlines