Forty-nine species of fish (ranging from 1/2-oz. minnows to 140 lb. paddlefish) reside in the river. Fishermen are most likely to catch goldeye, drum, sauger, walleye, northern pike, channel cat, carp, and small mouth buffalo. Of the six remaining paddlefish populations in the United States, the Upper Missouri's appears to be the largest in average size. Generally only taken by snagging in the spring during upstream spawning runs, they are excellent table fare. Occasionally floaters may see these lunkers roll on the surface. Other unusual species in the river are the endangered pallid sturgeon and shovel nose sturgeon.
Shoreline areas provide habitat for soft-shelled turtles, beaver and a wide variety of waterfowl.
The riparian zone immediately adjacent to the river bank is the most important vegetative type in the river valley. Riparian habitat, like that along the Upper Missouri, makes up less than 1% of the vegetative mosaic of the west, yet a greater variety of wildlife species depend upon it than any other vegetative type in the West. The riparian zone is a complex ecological community. It is fragile and its survival depends upon many of the natural forces that at first glance appear to be quite harsh.
A dynamic and essential element of the riparian zone is the river itself. Both vegetation and wildlife in this area are dependent upon normal fluctuations in water height and silt load and the river's tendency to meander. High flows recharge groundwater to levels needed by riparian vegetation and deposit nutrient rich soils across bottom lands. The river's meandering builds new gravel bars, islands, and new bottom lands to replace those that have become too high and dry for riparian vegetation.
Most of the 60 species of mammals, 233 species of birds, and 20 species of amphibians and reptiles that inhabit the Upper Missouri River valley are dependent in one way or another upon the riparian zone. Among the more common species are white-tailed deer and pheasant. While at one time they only visited the area during the late fall and winter, bald eagles are again nesting in cottonwood snags.
Between the riparian zones and the valley slopes are the bottom lands. One of the most common species living here is the prairie dog, a critter that is especially popular with visitors from outside the region. Mule deer and sharp-tailed grouse are also found in the valley slopes and coulees.
The plains above the valley provide habitat for antelope and sage grouse. Elk and bighorn sheep use a variety of these habitat types.
A very special place in the cross-section of the river valley is the cliff faces. Nooks and crannies in the cliffs provide perching and nesting habitat for the many raptors that inhabit the river area. Among them are the sparrow hawk, prairie falcon, and golden eagle.
In addition to those mentioned above, you might also see pronghorn antelope, coyotes, mountain lions, red fox, badger, raccoon, skunk, beaver, porcupine, muskrat, numerous waterfowl, songbirds, raptors and reptiles.