Idaho is situated in the northwest United States. The climate in this state is variable, ranging between semi-arid, humid continental, humid subtropical, and even subarctic. Generally, the east and north of the state receive more rainfall than the rest of the state.
Forests, mountains, rivers, wetlands, and lakes can be found in Idaho. These support a variety of flora and fauna, although somewhat surprisingly, just five species of salamander are found within the state.
Idaho Salamanders
1) Idaho giant salamander (Dicamptodon aterrimus)
- Native to Idaho and Montana
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The Idaho giant salamander is large, growing to lengths of 17 – 25 cm (6.7 – 9.8 in). It is dark brown in coloration, with small lighter brown spots and mottling across the dorsum. Some adults do not undergo metamorphosis and retain their external gills and aquatic lifestyle – this difference in ecology is not specific to populations, and different life histories may be seen within the same population.
The preferred habitat of Dicamptodon aterrimus is streams and small rivers, usually within coniferous forests. Individuals spend much of their time hiding underneath rocks or logs and tend to be more abundant in areas without roads and with old-growth forests. As well as the risks associated with road crossing, culverts also present challenges to this species, as they affect sedimentation levels and cause habitat disturbance.
Adult Idaho giant salamanders are voracious predators, consuming a diet of terrestrial invertebrates, snakes, salamanders, mice, and shrews. The larvae feed on aquatic invertebrates, and may also predate on small fish, larval salamanders, and tadpoles.
2) Long-toed salamander (Ambystoma macrodactylum)
- Native to western North America
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The long-toed salamander grows to 4.1 – 8.9 cm (1.6 – 3.5 in) in length. Its coloration is dark gray or black, with a dorsal stripe that can be yellow, olive, or green. The sides are speckled with blue or white in some individuals. This species can be found in much of Idaho, with the exception of the more southern counties.
Populations of Ambystoma macrodactylum are stable, however there are still threats present that may affect this species. These include the introduction of non-native fish species, which predate on larval salamanders, and diseases such as viral and fungal infections. Long-toed salamanders may also be threatened by the degradation of the coniferous forests and alpine meadows in which they reside.
Cannibalism is common among the larvae of long-toed salamanders: this feeding strategy may arise from high population densities, or increased hunger levels, and has been shown to enhance growth in those individuals partaking in it. Adult long-toed salamanders consume a diet of tadpoles, insects, worms, and small fish.
3) Couer d’Alene salamander (Plethodon idahoensis)
- Native to Idaho, Montana, and British Columbia
- Family: Plethodontidae
- Order: Urodela
- Conservation status: Least concern
The Coeur d’Alene salamander grows to around 13 cm (5.1 in) in length and has a dark brown or black body color, adorned with a wavy dorsal stripe which may be yellow, orange, or red. There may be some pale flecks on the sides, and the throat is usually yellow in color.
This species is found in the north of Idaho – specifically, it can be observed in Benewah, Bonner, Boundary, Clearwater, Idaho, Kootenai, Lewis, and Shoshone counties. It resides in wet, rocky habitats, usually close to streams or waterfalls – individuals are reliant on crevices between the rocks in which they can seek shelter. The diet of this salamander includes butterflies and moths (and their larvae), fly larvae, spiders, and snails.
Although the overall conservation status of the Coeur d’Alene salamander is that of least concern, populations may be at risk of decline due to habitat degradation, invasive species, pollution, and construction of roads.
4) Rough-skinned newt (Taricha granulosa)
- Native to the Pacific Coast
- Family: Salamandridae
- Order: Urodela
- Conservation status: Least concern
The rough-skinned newt is large, reaching up to 22 cm (8.7 in) in length. This salamander has a stocky build with a large head, and its dorsum is brown in color, with a yellow or orange underside. The skin becomes paler in color during the breeding season, and at this time the males’ skin also becomes very smooth.
Taricha granulosa is not especially common in Idaho, being found in just two counties: Idaho and Latah. The preferred terrestrial habitat of this species is forest or grassland in mountainous areas, while its aquatic habitat preferences include slow-flowing streams, ponds, and lakes. Rough-skinned newts feed diurnally, consuming a varied diet including crustaceans, insects, arachnids, worms, mollusks, and leeches.
The rough-skinned newt has a number of antipredator mechanisms. These include avoiding areas with chemical cues associated with predators, performing the Unken reflex (where they invert their body and raise their head and tail), and the secretion of tetrodotoxin from their skin.
5) Western tiger salamander (Ambystoma mavortium)
- Native to the western United States
- Family: Ambystomatidae
- Order: Urodela
- Conservation status: Least concern
The western tiger salamander has a thick body with a large head and grows to 15 – 20 cm (5.9 – 7.9 in) in length. Coloration in this species varies depending on the geographic region but is generally gray or black with yellow dots or bars across the dorsum.
Ambystoma mavortium has a patchy distribution in Idaho, with populations present in the southeast, southwest, and northwest. This species is adaptable and will occupy a wide range of habitats, as long as there is substrate to burrow in and water for breeding. Adults spend much of their time underground.
The larvae of the western tiger salamander feed diurnally on tadpoles and invertebrates such as crustaceans and insects. Adults consume a similar diet but may also eat small mammals. Although the conservation status of this species is that of least concern, populations may be threatened by pollution, road construction, and invasive species.
