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This Extinct Wolf-Sized Otter Demolished Prey With Its Forceful Bite

This 110-pound otter that lived 6 million years ago had a powerful bite, and was likely a top predator.

When people think of otters, “top predator” is not normally the phrase that jumps to mind. But that’s only because we live in an era of unfathomably cute otter species, which range in weight from 11 to 90 pounds.

Wind the clock back 6.24 million years, however, and you might have to confront Siamogale melilutra, an early otter that tipped the scales at 110 pounds and was roughly the size of a wolf. Paleontologists announced the discovery of this prehistoric species in the Journal of Systematic Palaeontology earlier this year, after finding its fossilized remains in China’s Yunnan province.


Now, a second study on the extinct aquatic mammal, published Thursday in Scientific Reports, shows that S. melilutra was not only an uber-otter, it also had an unexpectedly powerful bite.

Scientists led by Z. Jack Tseng, a computational anatomist at the University at Buffalo and a research associate at the American Museum of Natural History and the Natural History Museum of Los Angeles County, estimated the strength of the primitive otter’s jaws based on its cranial remains.

When they compared computed tomography (CT) scans of 10 living otter species’ skulls to simulations of the Siamogale’s head, they found that the extinct animal’s jaws were six times stiffer than expected.

Comparison of otter jaws. Image: Tseng et al., Scientific Reports, 2017

This correlates to a stronger bite force than extant otters, even accounting for the differences in size. It also suggests that Siamogale may have been an apex hunter in its swamp foodweb, capable of puncturing the shells of crabs, mollusks, and turtles, chewing through the bones of frogs and birds, or taking a chunk out of larger animals if threatened.

"We don't know for sure, but we think that this otter was more of a top predator than living species of otters are," Tseng said in a statement. "Our findings imply that Siamogale could crush much harder and larger prey than any living otter can."

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This is not the first time that the otter family has proved to be more fearsome than its cuddly appearance might imply. Humans are sometimes attacked by rabid otters, and the horrifying acts of depravity otters commit against baby seals include gratuitous killing and necrophilia. It goes to show that no matter how adorable you think these animals are, you otter keep your distance.

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