I have seen a otter run a sow coon and 3 little ones out of a hole in the crick. Also saw one turn on my mountain curr squirrel dog and whip him, and he can whip any possum and keep any coon treed on the ground all night if need be. I watch a pair of otters sneak swim up to the bank of my pond and watch my beagle working the brush and they looked like they were thinking about going after her, to the point I made myself noticed,good for them I had a bow instead of a gun. I helped turn the first ones loose years ago in our county. Big mistake on our part.JMO swimming cats