• View of the Monument across the Snake River

    Hagerman Fossil Beds

    National Monument Idaho


Idaho Springsnail

Enlarged view of the Idaho Springsnail

photo courtesy of FWS

The Hagerman area has five species of freshwater snails that are listed as threatened or endangered under the Endangered Species Act: the Snake River Physa (Physa natricaria), the Lanx (Lanx sp.)the Bliss Rapids snail (Taylorconcha serpenticola), the Utah valvata (Valvata utahensis), and the Idaho springsnail (Pyrgulopsis idahoensis).

The decline of the aquatic mollusk species has been primarily attributed to changes in the river from free-flowing, cold water to impounded, slower, warmer habitats. Another variable is the population increase of non-native invasive aquatic species such as the New Zealand mudsnail (Potamopyrus antipodarum).

Did You Know?

Sketch of the Hagerman Horse

The best known discovery is the Hagerman Horse, Equus simplicidens is the official Idaho state fossil. The Hagerman Horse Quarry, a national natural landmark, is recognized as one of the most important sites in the world related to the fossil history of the horse.