The spotted forms occur in the northern portion of its range.
A dividing line of 51°N latitude has been recognized between the two subspecies, with A. g. decorticatum occurring north of the line and A. g. gracile living to the south.

Populations with neotenic adults are widespread; the frequency of gilled adults increases with altitude such that adults at low and intermediate altitudes are almost all terrestrial, while adults at very high elevations are mostly neotenic.

An example of a paedomorphic population of the northwestern salamander occurs at Crater Lake, Oregon; the population is syntopic with Taricha granulosa.

Terrestrial adults live in mesic habitats ranging from grasslands to mesophytic forests.
Terrestrial adults are mostly fossorial, and are usually active on the surface only during fall rains and spring migrations to their aquatic breeding sites.
However, they can sometimes be found under logs and other surface debris outside of the breeding season.
The spotted forms occur in the northern portion of its range. A dividing line of 51°N latitude has been recognized between the two subspecies, with A. g. decorticatum occurring north of the line and A. g. gracile living to the south.
Populations with neotenic adults are widespread; the frequency of gilled adults increases with altitude such that adults at low and intermediate altitudes are almost all terrestrial, while adults at very high elevations are mostly neotenic.
An example of a paedomorphic population of the northwestern salamander occurs at Crater Lake, Oregon; the population is syntopic with Taricha granulosa.
Terrestrial adults live in mesic habitats ranging from grasslands to mesophytic forests. Terrestrial adults are mostly fossorial, and are usually active on the surface only during fall rains and spring migrations to their aquatic breeding sites. However, they can sometimes be found under logs and other surface debris outside of the breeding season.
Northwestern salamander