It Was a Wolf-Sized Otter, but With Jaws Like a Bear

Modern-day sea otters would prove no match for their 6-million-year-old, wolf-sized ancestors, who didn't need rocks to smash open mollusks. They could do that, and perhaps rip into tougher and larger prey, with a single bite from surprisingly powerful jaws, according to new research. In the latest study of Siamogale melilutra, described earlier this year as the largest otter ever found, researchers created a computerized model of the 110-pound animal's biting power. Turns out, it "had a jaw that was six times as strong as expected, based on what we see in living species," researcher Jack Tseng of the University at Buffalo tells the BBC. This, along with the animal's size, "implies that Siamogale was capable of crushing much larger and harder prey than observed in any of the living otter species," researchers write in Scientific Reports.

Indeed, "its giant size and high mandibular strength confer shell-crushing capability matched only by other extinct molluscivores such as the marine bear Kolponomos." Tseng says Siagmogale likely dined on crabs and mollusks just like present day sea otters. But it's also possible that the animal crushed the bones of turtles, birds, and small mammals as a top predator in its ancient habitat in what is now southwestern China, per New Atlas. So why are the jaws of today's otters relatively weak in comparison? One theory is that as the animals became more adept at using "tools" to gather their food, the need for uber-powerful jaws became less pressing. (More on Siamogale here.)