If you've ever seen a giant river otter in person, you might be surprised how big they seem when they're right in front of you. But that's nothing compared to the now extinct otters that lived six million years ago. Scientists working in China recently found the fossils of the previously unknown species that would have weighed in at around 110 pounds. The discovery of a complete skull and a few incomplete skeletons is a big jump forward in the knowledge about otter evolution as before that the only fossils scientists had to go by were a few shattered teeth. Like modern otters, they largely lived on shellfish.
If you're really into the science, you can read all the details in the Journal of Systematic Paleontology. Otherwise, you might want to stick with the summary on Gizmodo