Amphibians

Life in a Harsh Climate

Big Hole National Battlefield, located within the conifer-alpine ecoregion, hosts a limited but resilient amphibian population, which includes the Columbia spotted frog (Rana luteiventris) and the western toad (Bufo boreas). Despite the low amphibian diversity due to the high elevation and cold climate, these two species thrive in the park’s wetland habitats.

Amphibian Conservation Efforts

With their dependency on clean, wetland habitats, the amphibians of Big Hole serve as indicators of environmental health. National Park Service staff actively monitor the area’s water quality and manage invasive plant species to ensure the sustainability of these amphibian populations and their habitats.

 

Spotted frogs may be found in the wetland areas of the park.

NPS photo

Columbia Spotted Frog (Rana luteiventris)

• Appearance: The Columbia spotted frog is easily recognized by its upturned eyes and distinctive dark spots on its back. This unique appearance aids in camouflage among the wetlands, allowing the frog to blend into the shadows and textures of its environment.

• Breeding: Spotted frogs breed from February through July, depending on their specific location within their range. They produce a unique, rhythmic call that consists of a rapid series of hollow sounds, much like tapping on a hollow log. This call is one way researchers and park visitors can identify them in their habitats.

• Cold-Weather Survival: In winter, spotted frogs burrow deep into the mud of their wetland habitats to survive the cold. They enter a state of inactivity, during which they do not eat and instead absorb oxygen through pores in their skin. This adaptation allows them to endure the harsh winter months without needing to surface.

• Population: According to a 2002 study, Big Hole’s wetlands support an estimated 2,000 Columbia spotted frogs. Researchers based this number on observations of tadpoles and other life stages around the Big Hole River and nearby wetland areas.

• Environmental Sensitivity: As amphibians, spotted frogs are highly sensitive to environmental changes, especially pollution in the air, soil, and water. The National Park Service actively monitors water quality and treats invasive plant species in Big Hole to protect the frog’s habitat and ensure these sensitive ecosystems remain healthy.

 

Western toads are residents of Big Hole NB and can blend in quite well with their surroundings.

NPS photo

Western Toad (Bufo boreas)

• Appearance: Western toads are distinctive for the white or cream-colored stripe running along their backs. Their body coloration can vary, often appearing dusky, yellowish, tan, gray, or greenish with clusters of dark warts, giving them a textured, rugged appearance that helps them blend into their surroundings.

• Movement and Sound: Unlike many other amphibians that are known for their hopping, western toads generally prefer to walk. Their unique call is a mellow, high-pitched chirrup or “plinking” sound, which resembles the soft peep of a chick and can be heard echoing through their habitat during active periods.

• Ecological Role and Sensitivity: Western toads rely heavily on clean, healthy wetlands for breeding, foraging, and overall survival. Highly sensitive to changes in their environment, they are vulnerable to pollutants in water, soil, and air. Their presence in Big Hole National Battlefield is a reminder of the need for ongoing conservation and monitoring efforts to maintain the health of these critical wetland habitats.