I once had a bunch of them regularly visit a dam close to my house. My dogs would bark at them, but usually kept a respectful distance. On one of these occurrences, I went to see what the fuss was about. One of my dogs, a Boxer X Boerboel, who had more guts than brains and was likely encouraged by my presence, decided to attack one of the intruders. The little otter grabbed him by the nose and dragged the 40kg dog into the water. Only when all the other dogs and myself came to his rescue, did the otter release him. Physical damage was negligible, but the dog's ego took a severe beating...

Their tracks showed that they walked about 2 km's over dry land from a nearby river, to come fish in my dam.