New research undermines 'killer walrus' theory

DUNEDIN, New Zealand, May 9 (UPI) -- Previous studies have suggested the species Pelagiarctos thomasi once hunted and ate marine mammals -- dubbing it the "killer walrus." New analysis of the ancient walrus's teeth, however, offer no indication of such behavior.

"We found it has an enamel layer reasonably similar to that of modern New Zealand fur seals and sea lions, which are fish and squid eaters," Caroline Loch, a researcher with the University of Otago in New Zealand, said in a news release.

Loch and her colleagues compared the fossilized teeth of Pelagiarctos thomasi, recovered in California, to the teeth of modern fur seals and sea lions using scanning electron microscopy. The results revealed a similar enamel structure -- one suited for a generalist, not a mammal-hunter.

Researchers say the ancient walrus's teeth would have cracked trying to crush through mammal bones. Instead, its teeth were likely used to eat fish.

Loch serves on the dentistry faculty as a researcher fellow at Ortago's Sir John Walsh Research Institute.

"Features and structures of the enamel layer have long been associated with differences in diet and tooth usage among animals, and can also help in the understanding the relationships among fossil and living species," Loch said. "Teeth are not only the focus of modern dentistry, but also valuable tools for biologists, archaeologists and paleontologists."

The new research was published in the journal The Science of Nature.