Muskrats are 95% herbivores...so I would be discinclined to believe it was a muskrat.
![thinking :thinking:](https://www.worldwidewatergardeners.org/forum/Smileys/smilies_smf/thinking.gif)
(or a beaver for that matter)
Muskrats here go right for the cattails and water lilies, & other water plants.
Muskrats are not very active in winter, same with beavers.
In fact, muskrats like to co-habitate with beavers as opportunists,
often making their dens on the outside edges of a beaver dam.
(and then poach from the beavers winter stores)
Otter, ermine/mink, weasel, yes, because these animals are mostly carnivores.
And they are active all winter, do not hibernate or slow down at all.
In fact, muskrat is high on the menu of these animals.
![Shocked :o](https://www.worldwidewatergardeners.org/forum/Smileys/smilies_smf/shocked.gif)