Idaho giant Salamander, adult
Idaho Giant Salamander
Dicamptodon aterrimus
(Dicamptodontidae)
Montana Species of Concern
Global Rank:
G3
State Rank:
S2
Agency Status
USFWS:
USFS:
none
BLM:
none
General Description
Adults have light or tan bronze marbling on a dark brown or black background. They are heavy-bodied, with a large head and muscular legs; body length varies from 3.5 to 8 inches. Eggs and Larvae: Larvae are identified by their short, bushy, external gills; their large size; a dorsal fin starting at or behind the rear limbs; and their stream habitat. Other larval salamanders in Montana live in ponds have long, feather gills, and a dorsal fin originating far forward of the rear legs.
Migration
Nonmigratory.
Habitat
Known to occur up to 2160 m in elev. (Nussbaum et al. 1983). Transformed adults, although seldom seen, inhabit moist coniferous forests where they may be found under logs, bark, or rocks. They are most active on warm, rainy nights. Larvae are usually found in swift, cold mountain streams, but may occasionally be found in lakes or ponds (Reichel and Flath 1995).
Food Habits
Larvae: diet influenced by size, consisting of 52% Trichoptera larvae, 46% Plecoptera nymphs, 30% Coleoptera larvae, 28% Ephemeroptera nymphs/Coleoptera adults. ASCAPHUS larvae (14%) may be important food for larger larvae (Metter 1963). Females do not feed during 7 months spent in nest with eggs (Nussbaum et al. 1983).
Ecology
Neoteny uncommon in small streams, but neotenes may constitute major breeding force in populations in large streams and ponds/lakes (Nussbaum and Clothier 1973).
Reproductive Characteristics
Ovipost in spring (May in coastal regions) and fall (noted in ID); incubation 275 days (Nussbaum 1969). Larvae hatch at SVL 18.25 mm, but do not feed for 3-4 more months until 24.43 SVL. Metamorphose during second year (Nussbaum and Clothier 1973). Females do not feed during the 7 months spent in nest with eggs; therefore, they likely only breed during alternate years (Nussbaum et al. 1983).
Citations & Sources
- Maxell, B., Werner K.J., Hendricks, and P., Flath, D., 2003. Herpetology in Montana. Society for Northwestern Vertebrate Biology
- Metter, D. E. 1963. Stomach contents of Idaho larval DICAMPTODON. Copeia 1963:435-436.
- NatureServe Explorer: An online encyclopedia of life [web application]. 2002. Version 1.6 . Arlington, Virginia, USA: NatureServe. Available: http://www.natureserve.org/explorer. (Accessed: March 20, 2003 ).
- Nussbaum, R. A. 1969. Nests and eggs of the Pacific giant salamander, DICAMPTODON ENSATUS (Eschscholtz). Herpetologica 25:257-262.
- Nussbaum, R. A., E. D. Brodie, Jr. and R. M. Storm. 1983. Amphibians and reptiles of the Pacific Northwest. Univ. Press of Idaho. 332 pp.
- Nussbaum, R.A. and G.R. Clothier. 1973. Population structure, growth, and size of larval Dicamptodon ensatus (Erscholtz). Northwest Science 47(4):218-227.
- Reichel, J. D. and D. Flath. 1995. Identification of Montana's amphibians and reptiles. Montana Outdoors 26(3):15-34.
- Thompson, L. S. 1982. Distribution of Montana amphibians, reptiles, and mammals. Montana Audubon Council. 24 pp.
