Lutra Erect can be found before and after the destruction of the Lighthouse. It is first found atop the Lighthouse, going circles on the very top of the tower. You need to reach one of the platforms that expand once the shield is deployed to get a proper view of the otter and take a picture of it. After the destruction of the Lighthouse, you need to go to the third floor, and stand effacing the ocean. The Two-Legged Otter will be right in front of you, unjust behind the knee-high destroyed wall.