Giant otters the size of wolves lived in rivers and lakes in south-western China some 6.2 million years ago, scientists have discovered.
The otter, named Siamogale melilutra, weighed about 50kg (110 pounds) and measured up to 2 metres (6.6 feet) in length, according to research published in the Journal of Systematic Palaeontology.
Fossils of the otter, which include a skull, jawbone and teeth, were discovered by palaeontologists at the Shuitangba open-pit lignite mine in China's Yunnan province.
The skull had been crushed during the fossilisation process, so scientists used a CT scanner to help virtually reconstruct a complete image.
The fossils also revealed that the otters had a powerful jaw with large cheeks, believed to have helped it eat large shellfish and freshwater mollusks, which were found abundantly at Shuitangba.
"From the vegetation and other animal groups found at Shuitangba, we know that it was a swampy, shallow lake with quite dense vegetation", said Dr Denise Su, Curator and Head of Paleobotany and Paleoecology at the Cleveland Museum of Natural History.
The scientists hope that further studies of the otters will yield more answers as to how they lived their life.
"The discovery of the otter helps solve some questions but opened the door to new questions...why was it so large, how did it crack open mollusks for food and how did it move in the water and on land?" said Dr Wang Xiaoming, Head of Vertebrate Palaeontology at the Natural History Museum of Los Angeles County.
"Continued studies will address these fundamental questions and give us a more complete picture."
Currently, the world's largest otter is the South American giant river otter, which weighs up to 31kg.
BONUS: Lazy sea lion decides this car roof is a great place for a nap