The coastal giant salamander (''Dicamptodon tenebrosus'') is a species of

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

in the genus ''Dicamptodon'' (Pacific giant salamanders). It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the

Pacific Northwest The Pacific Northwest (PNW; ) is a geographic region in Western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though no official boundary exists, the most common ...

of North America. There are three closely related species to this taxon: ''D. ensatus'' (

California giant salamander The California giant salamander (''Dicamptodon ensatus'') is a species of salamander in the family Ambystomatidae. ''Dicamptodon ensatus'' is endemic to California, in the western United States. The species once additionally included individuals ...

), ''D. copei'' (

Cope's giant salamander Cope's giant salamander (''Dicamptodon copei'') is a species of salamander in the family Dicamptodontidae, the Pacific giant salamanders.Behler, J. L. and F. W. King. (1979) ''National Audubon Society Field Guide to Reptiles and Amphibians'', Kn ...

), and ''D. aterrimus'' ( Idaho giant salamander).

Description

The coastal giant salamander can reach up to in total length as a terrestrial adult, and in paedomorphic forms, making it the largest terrestrial salamander in North America. The coastal giant salamander has stout limbs with four toes on the front feet and five toes on the back feet. The species tail is around 40 percent of the total length of the salamander and is laterally compressed. The head, back, and sides have a marbled or reticulate pattern of dark blotches on a light brown or brassy-colored background. The head is broad with a shovel-like snout and a fold of skin across the throat called the gular fold. The

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

s are medium in size and have a brass-flecked iris and a large black pupil. This species is one of the few salamanders capable of vocalizing.

Life history

A female coastal giant salamander will lay her eggs in moderate to slow flowing mountain streams under rocks and crevasses, hatching in early to mid spring. The coastal giant salamander, being a member of the genus ''Dicamptodon'', exhibits two distinctive phases within its life; an aquatic larval stage with filamentous gills and an elongated tail with a caudal fin (similar to that of a tadpole), and a terrestrial adult form losing their caudal fin and filamentous gills, and instead developing robust legs and a pair of internal lungs.

Neoteny

Some coastal giant salamander

larvae A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...

continue to grow into adults and become sexually mature without losing their external

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

s. This process is called

neoteny Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the Physiology, physiological, or Somatic (biology), somatic, development of an organism, typically an animal. Neoteny i ...

. Neoteny is particularly common in the British Columbia populations. Adult-sized neotenes have a uniform brown coloring on their heads, sides, and backs.

Behavior

Activity level

Terrestrial adult coastal giant salamanders spend most of their time underground in burrows, emerging to reproduce and forage on rainy and humid nights.

Foraging and diet

Adult coastal giant salamanders, like most of the genus ''Dicamptodon'', are opportunistic feeders feeding on anything they can fit in their mouth. This may include, but is not limited to; slugs, insects, worms and other invertebrates as well as small vertebrates such as small rodents, snakes, and other giant salamanders. In the larval stage, coastal giant salamanders will feed on small macroinvertebrates such as insect larvae as well as small fish and mollusks. Both adult and larval coastal salamanders have been recorded consuming other individuals of the same species.

Defense

When threatened an adult coastal giant salamander will arch its back and lash its tail forward. Coastal giant salamanders excrete toxins through their skin which will cause nausea if consumed. Adult coastal giant salamanders can produce a painful bite.

Range

The coastal giant salamander is

to the Pacific Northwest, found in Northern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

, and southern

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

Habitat

Aquatic stages are found in clear, cool or cold, well-oxygenated streams, and sometimes also in mountain lakes and ponds. Metamorphosed adults are found in humid forests (under rocks and logs, etc.), near mountain streams, or rocky shores of mountain lakes.

Conservation

Pacific giant salamanders are protected from being killed or collected under the Wildlife Act in

References

{{Taxonbar, from=Q2277209 Dicamptodon Amphibians of Canada Amphibians of the United States Fauna of California Natural history of Oregon Natural history of Washington (state) Amphibians described in 1852 Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard