Around 6 million years ago, an ancient giant otter skulked its way through the swamps and waterways of China, on the hunt for anything it could get its powerful chops around. The massive aquatic animal was around twice as large as any living otter, and would have been comparable to a wolf in size.
Now new research is suggesting that it may also have matched wolves in its place on the food chain. Analysis of the otter's skull shows that it would have been a top predator at the time, likely to have crunched down on giant clams, turtles, and even the bones of birds. With its powerful bite and extraordinary size, the creature would probably have dominated the wetlands in which it lived, the authors argue in their paper published in Scientific Reports.
The extinct otter is one of the largest known to have ever existed. Officially known as Siamogale melilutra, it would have weighed 50 kilograms (110 lbs), twice that of the biggest alive today.
“We started our study with the idea that this otter was just a larger version of a sea otter or an African clawless otter in terms of chewing ability, that it would just be able to eat much larger things,” explained the University at Buffalo’s Z. Jack Tseng, who led the research. “That’s not what we found.”
To figure out exactly how powerful the prehistoric otter’s bite was, the researchers looked to their living counterparts. Of the 13 extant species, they were able to create detailed 3D models of 10 of them, and accurately calculate the biting force for each one. From this they found that as they went from largest species to smallest, the jaw strength actually increased in a linear relationship.
But when they threw in the reconstruction of the ancient giant otter’s skull, based on CT scans of the nearly complete fossil skull revealed earlier this year, they found something surprising. Based on the relationship uncovered among living species, they thought that the hefty extinct animal would have a relatively weak jaw, but instead, it was an impressive six times sturdier than expected. This, they suggest, would have made it a fearsome hunter.
“We don’t know for sure, but we think that this otter was more of a top predator than living species of otters are,” said Tseng. “Our findings imply that Siamogale could crush much harder and larger prey than any living otter can.”
The environment in which the otters were living would have been swamps and lakes surrounded by dense forests, providing a smorgasbord of prey such as fish, turtles, frogs, birds and giant clams. The robust jaws would have allowed the predators to exploit all of these foods, enabling them to crush solid bones and shells.