A couple decades ago, river otters came close to extinction due to habitat loss, pollution and trapping. When taking photos of the swans in open lake water, I was excited to see this otter come by. However, by the look of the swans, I was the only one welcoming our visiter. After doing some research, I learned why the swans were so concerned. Although otters don't prey on species as large as swans, that doesn't mean an otter wouldn't attack a swan if it felt challenged by the swan.