On my last walk in the local peat bog, I saw this heap of grass, reeds and other stuff sitting in a pool:
Olympus Stylus 1s, 100mm, ISO200, f8, 1/160s
This doesn't just happen, and we have no species like beavers in my region that build lodges, or at least that's what I thought.
It turned out this is the winter lodge of muskrats. I remembered seeing rats here last November, which alarmed me a bit at the time, because rats can destroy whole populations of amphibians. On closer inspection, however, they turned out to be muskrats, and they are mainly herbivores and not really rats at all, but members of the Arvicolinae family, which also includes voles and lemmings. Further reading told me they build lodges for the winter in pools.
Muskrats are most active at dusk and at night. They are strong swimmers that will dive at the first sign of trouble, and they can stay under water for about 15 minutes. You can imagine it is not easy to get a photo, but last November, after an hour of sitting still in semi-hiding I managed to take one reasonable photo of a muskrat before it noticed me and disappeared:
Olympus Stylus 1s, 300mm, ISO800, f4, 1/40s
I have been told muskrats are very tasty, making them one of the few examples of tasty, imported American food (muskrats are not native here). They appear on restaurant menus in Flanders and the South of The Netherlands as waterkonijn ("water rabbit"). Apparently, people don't want to eat animals that are called "rat".