Siredon gracilis Baird, 1859, Cascade Mountains, close to latitude 44° north, Oregon, United States. Two subspecies usually are acknowledged, though scientific proof for that is weak.
These pretty massive salamanders develop to 8.7 in (220 mm) in size. They are uniformly brown or black and breed each as metamorphs and paedomorphs. Metamorphosed adults have intensive poison glands within the parotoid area and on the bottom of the tail; when disturbed, they typically secrete a white, sticky, poisonous secretion.
The northwestern salamander happens in moist fir and redwood forests of northwestern North America from Sonoma County, California, United States, to British Columbia, Canada.
Paedomorphs of this species are commonest in everlasting lakes at increased elevation, whereas metamorphs have a tendency to happen in conifer forests at decrease elevations. Unlike many different ambystomatids, paedomorphs can coexist with predatory fish by shifting their exercise patterns and changing into nocturnal.
Individuals of this species spend most of their grownup life in underground burrows, though they might be discovered on the floor throughout rains. When these salamanders are disturbed, they assume a inflexible posture with the tail partially raised and secrete a white poisonous liquid from the parotoid area of the top and from the higher ridge of the tail.
FEEDING ECOLOGY AND DIET
Larval northwestern salamanders feed on zooplankton, all kinds of aquatic invertebrates, and frog tadpoles; bigger people take bigger prey. Terrestrial adults presumably feed on earthworms and different invertebrates.
Reproductive maturity is reached in two to a number of years, relying on elevation. Populations differ by way of metamorphosis/paedomorphosis; it's not recognized whether or not the 2 sorts interbreed.
No apparent declines have been documented, though there could also be proof that populations are lowered in logged or secondary-growth forests.