Amphibians
Coastal Giant Salamander
Dicamptodon tenebrosus · also called coastal giant salamander, Pacific giant salamander
The coastal giant salamander is the heavyweight of North American land salamanders — a thick-bodied, mottled predator of cold Pacific Northwest streams that will eat a mouse or a small snake, bite hard enough to draw blood, and, unusually for a salamander, bark at you.
Overview
Coastal giant salamanders live along cold, clear, forested streams from southwestern British Columbia to northwestern California. Larvae grow in the stream; many then transform into terrestrial adults that live in the moist forest near the water, under logs and rocks and in burrows, while some remain aquatic gilled adults for life. It is the largest salamander in North America that regularly lives on land, reaching about 35 centimetres.
A top predator
A full-grown coastal giant salamander is a serious carnivore for its ecosystem. Recorded prey includes fish, frogs, other salamanders (it is cannibalistic), banana slugs, small garter snakes, shrews, and mice, ambushed from cover at night. It has strong jaws and sharp teeth.
It barks
Almost all salamanders are silent, but the coastal giant salamander can produce a low bark, rattle, or yelp when alarmed or seized — a startle tactic. Combined with its size, bite, toxic tail-skin secretions, and habit of lashing its tail, it is an unusually assertive amphibian.
Two ways to grow up
The species has a flexible life history: in many streams larvae metamorphose onto land, but in cold, stable, productive streams a proportion stay aquatic and gilled for life, breeding as paedomorphic adults. The path taken depends on conditions in the natal stream.
Status
The coastal giant salamander is Least Concern and common in intact stream habitat, but it is sensitive to logging and the sedimentation and warming of streams that follows.
Coastal Giant Salamander: common questions
How big is the coastal giant salamander, and is it really the biggest?
Adults reach about 30 to 35 centimetres total length and can be quite heavy-bodied, making this the largest salamander in North America that lives a substantial part of its life on land. The hellbender and the (introduced range of the) mudpuppy are fully aquatic; among land-capable North American salamanders, the giant salamanders of the genus Dicamptodon are the largest. Worldwide, the Chinese and Japanese giant salamanders are vastly bigger, but they are entirely aquatic — as terrestrial salamanders go, the coastal giant salamander is among the largest anywhere.
Do salamanders bark? This one does?
Yes, which is unusual. The great majority of salamanders are silent, lacking the vocal apparatus of frogs. The coastal giant salamander is one of a handful of species that can make a sound — a low, rough bark, rattle, or yelping cry, produced when the animal is alarmed, cornered, or grabbed. It is thought to work as a startle tactic, buying a moment for the salamander to escape or bite, in the same way many otherwise-silent animals produce a sudden noise under threat. Combined with its size, strong bite, and tail-lashing, it makes the coastal giant salamander a surprisingly assertive amphibian.
What does an animal this size eat?
A lot, and a wide range. Larvae and juveniles take aquatic invertebrates, but a full-grown coastal giant salamander is a genuine top predator of small forest-stream ecosystems. Recorded prey includes fish, tadpoles and adult frogs, other salamanders (including smaller coastal giant salamanders — they are cannibalistic), banana slugs, large insects, small garter snakes, shrews, and mice, which it ambushes from the streambank or from under cover. It hunts mostly at night and in wet weather.
Why do some stay in the water as giant "tadpoles"?
The coastal giant salamander has a flexible life history. In many populations, larvae grow in the stream for a year or two and then metamorphose — losing their gills, developing lungs, and moving onto land as the terrestrial adult. But in some populations, especially in cold, stable, productive streams, a proportion of individuals never metamorphose. They keep their gills and aquatic form, grow to full adult size, and reproduce as "paedomorphic" or "neotenic" adults. Which path an individual takes seems to depend on conditions in its natal stream — where the water is cold and reliable and the land is harsh, staying aquatic can be the better bet.