North American Beaver (Class 2)
The largest rodent in North America, this species is iconic for its ability to build dams and lodges on river systems. This species is widepread in North America, including in Alaska, Canada, and most of the continental United States. This plump rodent would live all along the river that runs through the center of Mississippi Acres and also in the channels of the river that flow away from the main part of it.
Since Mississippi Acres is a blackwater ecosystem that already has slow-moving water, the addition of actual beaver dams blocking parts of the river and creating beaver ponds seems unnecessary. That being said, beavers don't always create beaver ponds, in fact on larger rivers they often just build their lodges on the riverbank as a sort of reinforced burrow. Riverbank lodges could be added to various random locations along Mississippi's river system, and each of these would function similarly to the burrows that the European Rabbits use currently.
The main way to hunt beavers would be to ambush and shoot them in their feeding zones, which would be located a short distance from their lodge, and often a few hundred meters downriver from them. Beavers would feed around dawn and dusk, spending the rest of their day either hiding out in their lodges or traveling between their feeding zones and their lodges. When spooked, a beaver would flee to the nearest deep water (like Alligators do) slap their tail on the water (which would be their fleeing call) and then dive into the water for safety and swim to their lodge. When traveling to and from feeding zones, beavers would swim on top of the water, making them a difficult target. However, when traveling on land to their feeding zones, they would be an easy target for opportunistic hunters. Beavers have poor eyesight, making them easy to sneak up on, as long as they don't smell you.
North American Beavers could also be added to Layton Lake, Yukon Valley and New England Mountains.