An ancient "killer walrus'' may have been wrongly accused.
University of Otago scientists have just cast further doubt on a theory that the extinct "killer walrus'' preyed on seals and other small marine mammals.
The research team's findings about the internal structure of tooth enamel in a fossil walrus from California, Pelagiarctos thomasi, has recently been published in an international journal, The Science of Nature.
The scientists also analysed the teeth of modern pinnipeds, the New Zealand fur sea and sea lion. Pinnipeds include walruses, seals and sea lions.
Study co-author Dr Carolina Loch said it was "quite important'' research.
It was the first time the enamel ultrastructure of fur seals and sea lions, as well as the extinct walrus Pelagiarctos, had been studied using a scanning electron microscope.
"Pelagiarctos was originally thought to have been a 'killer walrus' that fed on large prey such as other marine mammals,'' Dr Loch said.
But the researchers 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''.
Its enamel structure meant this walrus was unlikely to be up to crunching through large bones without cracking its teeth - suggesting that it was a dietary generalist like the modern New Zealand pinnipeds.
The study also highlighted the value of using techniques and methods common in dentistry to answer questions with broader implications for biology and evolution.
"Teeth are not only the focus of modern dentistry, but also valuable tools for biologists, archaeologists and palaeontologists,'' she said.
The study was conducted by Dr Loch, a research fellow at the Otago School of Dentistry, US-based Otago geology graduate Dr Robert Boessenecker, Dr Morgan Churchill and the late Prof Jules Kieser.
