Dicamptodon
aterrimus
(Idaho Giant Salamander)
Key Characteristics:
|
Adult Characteristics |
Larval Characteristics |
Egg Characteristics |
|
Robust body |
Attached singularly |
|
|
Marbled pattern |
. | . |
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: |
|
|
State Rank: |
S3 |
Important
State References:
Cassirer, E.F. 1995. Wildlife
inventory, Craig Mountain, Idaho. Idaho Dept. Fish & Game, Lewiston. 182 pp.