These Proto-Wombats Could Chomp Like Nobody’s Business

Misaki Ouchida
Misaki Ouchida / Misaki Ouchida

Move over, T. rex—there’s a new Chompin’ King of the Cretaceous. Paleontologists say a badger-sized marsupial named Didelphodon vorax may have had the strongest bite force of any mammal that’s ever lived. They published their findings in the journal Nature Communications.

Until quite recently, very little was known about Didelphodon and its cousins from the Cretaceous Period. Scientists really had only small fragments of teeth and bones to go on. From these, we knew that D. vorax was the biggest in the family, and that it was durophagous, or a bonecracker, biting down hard to crush its prey. But bigger pieces have begun to emerge from an expanse of rocks along Hell Creek, Montana. Over the last 15 years, paleontologists excavated an additional two Didelphodon jaw bones, part of a snout, and a near-complete skull.

Image Credit: Burke Museum of Natural History & Culture

Analysis of these new pieces revealed that the scrappy little marsupials had evolved much earlier than previously thought—about 10 to 20 million years earlier.

Researchers put the fossils through computed tomography (CT) scanners to get a good idea of how they looked inside and out. Then they used the resulting 3-D images to estimate how long D. vorax’s jaw muscles would have been and how they would have attached to its skull. To get an idea of the animal’s diet, the team also analyzed patterns of wear on the fossilized teeth.

The bones told a story of a tough and not particularly fussy creature. D. vorax likely weighed between about five and 11 pounds. It ate pretty much whatever it could find, from plants and worms to spiders, crayfish, and shellfish. And its jaws were amazing; the researchers say this little critter may have had the strongest bite of any mammal that’s ever lived. In technical terms, its BFQ (bite force quotient) is 201. An African lion’s jaws max out at around 151.

These findings upend everything we thought we knew about Mesozoic mammals, lead author Gregory P. Wilson of the University of Washington said in a statement. "Instead of a shrew-like mammal meekly scurrying into the shadows of dinosaurs, [D. vorax] would've been a fearsome predator on the Late Cretaceous landscape—even for some dinosaurs."