Scientists in China have dug up the skull of a "wolf-sized" ancient species of otter which lived over 6 million years ago.
Researchers said that the otter, called Siamogale melilutra would have been around 2 metres long, twice the size of a modern day otter.
It had large powerful jaws capable of crushing hard objects such as shellfish.
Today's sea otters use rocks as tools to help them break into hard foods
Researcher, Xiaoming Wang, said "If Siamogale melilutra was not smart enough to figure out tools, perhaps the only option left was to develop more powerful jaws by increasing body size."
The skull of Siamogale melilutra was unfortunately crushed over millions of years and scientists had to use special software to recreate what the skull looked like before it was flattened.
This discovery is exciting but also brings in more questions such as "why was it so big?"
Professor Ji Xueping who was part of the expedition which found the skull said the question of the otters size was "a big question for further study".