Today, students in Vertebrate Natural History at SLU visited some impressive beaver habitat along the Wolf Lake trail. Starting from the southern trailhead and following the "blue" trail on the Nature Up North trail map, we encountered a series of smallish beaver dams along a creek as we hiked toward Moon Lake. At the top of the series of dams is a larger beaver pond with clear signs of current activity. We continued another 100 meters along the trail to the very large (about 7-8' high) beaver dam depicted in the photo with students in front of it. This dam is a great example of why beavers are considered "ecosystem engineers". We also looked at the lodge, shown in one of the pictures. The lodge is clearly being maintained, as evidenced by the fresh mud and sticks. We could see the trail the beavers follow up onto the lodge for maintenance. They must have heard us at their door - a few minutes after our arrival at the lodge, we heard a gurgling noise from within in, and a few minutes after that, spotted a beaver on the pond about 30 meters away. The beaver promptly smacked its tail on the water to tell us to buzz off. We noticed a second beaver swimming out from the lodge, as well. We left them in peace, but were certainly impressed by their construction skills.