Dicamptodon aterrimus
(Idaho Giant Salamander)

Key Characteristics:

Adult Characteristics

Larval Characteristics

Egg Characteristics

Inconspicuous
costal grooves

Small gills (adapted to streams)

Unpigmented eggs

Robust body
and head

Yellowish patches
on sides and back

Attached singularly

Marbled pattern
of black on brown

. .

General Description:
As the name suggests, the Idaho Giant Salamander is the largest salamander found in the state of Idaho. These salamanders have robust bodies and heads and can grow to lengths of 33cm total length. Idaho Giant Salamanders have a dark marbled pattern of spots or blotches on a brown, gray, tan or copper ground color. Unlike the Tiger Salamander, which it superficially resembles, the Idaho Giant Salamander lacks the readily visible costal grooves. Another characteristic of these salamanders is that the fourth toe on the hind foot only has three segments (Stebbins 1985).

The larvae of this salamander are adapted to living in streams, as shown by their short, small gills. Other distinguishing characteristics of these larvae are yellowish blotches on a tan ground color. Some individual larvae of this species can become sexually mature while maintaining the larval form, this is called paedomorphosis.

Idaho Giant Salamander eggs are unpigmented and attached singularly under submerged logs and rocks. The 6.5mm diameter eggs may be laid in groups of 135-200

Idaho Distribution:
In Idaho, these salamanders are restricted to the north-central forested areas.

Habitat:
Larvae usually inhabit clear, cold streams, but are also found in mountain lakes and ponds. Adults are found under rocks and logs in humid forests, near mountain streams, or on rocky shores of mountain lakes.

Idaho Giant Salamanders are generally found in moist coniferous forests. The transformed adults are secretive and seldom found in the open, but can be found in moist areas such as under logs and bark. They need a water source for reproduction. Often, this is a the headwaters of a mountain stream, a spring or mountain lake.  Idaho Giant Salamander larvae are more frequently encountered and may be locally common.  They and are usually found under rocks in mountain streams.

Diet:
Larvae feed on wide variety of aquatic invertebrates as well as some small vertebrates (e.g., fishes, tadpoles, or other larval salamanders). Adults eat terrestrial invertebrates, small snakes, shrews, mice, and salamanders.

Ecology:
Hibernates/aestivates. Usually reaches sexual maturity (in both larval and terrestrial forms) at sizes greater than 115 mm (snout to vent length).

Reproduction:
Breeding occurs in spring and fall. Female lays clutch of 135-200 eggs in spring, and guards eggs until hatched. Life history is variable and complex. At some sites, all larvae metamorphose and reproduce as terrestrial adults. At other locales, high percentage of individuals are paedomorphic.

Conservation:

Status:

Unprotected nongame species

Global Rank:

G3

State Rank:

S3

Important State References:
Cassirer, E.F. 1995. Wildlife inventory, Craig Mountain, Idaho. Idaho Dept. Fish & Game, Lewiston. 182 pp.


Original images provided by Charles R. Peterson and Edmund D. Brodie, Jr., 1997
Species description, key characteristics and original html by John Cossel Jr. 1997.
Species ecological information from Groves et al.© 1997.
Updated design, image optimization and final revision by Ean Harker ©1999, 2000.
Adaptation for DAI by Stephen Burton and Mike Legler 1999.