Description: The arboreal salamander is large for a plethodontid salamander, at about 10 to 19 cm total length. Adults are robust, with muscular jaws and very broad and triangular heads. The tail is semi-prehensile. Color is medium to dark brown above, creamy white below. Small yellow or cream-colored spots are usually scattered over the dorsal surfaces.
Sessions and Kezer (1987) found that populations at the northern extreme of the range were chromosomally differentiated from those south of Mendocino County.
Distribution: From northern coastal Baja California, north through the coast ranges as far as Humboldt County. Disjunct populations occur in the foothills of the central Sierra Nevada and on a number of islands off the California coast. Populations occur from sea level to about 600 meters elevation. According to Petranka (1998), populations are generally absent from areas with less than 25 cm of annual precipitation.
In Humboldt County, there are historical records as far north as the vicinity of Eureka. In suitable habitat, the species remains common in parts of southern Humboldt County.
Habitat: The arboreal salamander is strongly associated with open oak woodlands. In Marin and Sonoma Counties, where this species is common, it is often found on steep slopes among coast live oak and black oak with less than 50 percent canopy cover. In Humboldt Redwoods State Park, it occurs around the margins of grassland openings on south facing slopes, usually in proximity to scattered Oregon oaks (K. Mierzwa, pers. obs.). In the Sierra Nevada, yellow pine and black oak woodland is the typical habitat (Petranka, 1998).
In the rainy season, individual salamanders may be found under or within woody debris on the ground. Under drier conditions large numbers have been reported to congregate inside cavities of oaks up to at least 10 meters above the ground. Dunn (1926) described the removal of about 100 arboreal salamanders and 12 egg masses by workers cleaning out cavities in coast live oaks on the University of California Berkeley campus.
Arboreal salamanders also readily utilize other damp, enclosed spaces. Stebbins (1951) collected about a dozen of these salamanders from crevices inside a concrete structure enclosing a spring in San Benito County.
Because the arboreal salamander is associated with relatively open areas, it may be tolerant of some forms of disturbance. Bury and Martin (1973) noted this species within logging clearings in redwood forest. In Humboldt County, multiple individuals have been observed within recently burned areas (K. Mierzwa, unpublished field notes).
Behavior: Nothing is known of breeding or courtship behavior. Females deposit about 12 to 19 eggs underground or in tree cavities in June and July. The female guards the eggs, which hatch after three or four months. Age at sexual maturity is at least three years. Arboreal salamanders feed on a wide variety of invertebrate prey, and at least occasionally on smaller salamanders. Adults are territorial at some times or under certain circumstances, and agonistic behavior is apparently not uncommon (Staub, 1993).
Conservation: Although arboreal salamanders are common within much of their range, oak woodland habitat is not well represented in protected areas and is at risk for a variety of reasons including development, conversion to vineyards, and disease.
Bury, R. B., and M. Martin. 1973. Comparative studies on the distribution and foods of plethodontid salamanders in the redwood region of northern California. Journal of Herpetology 7:331-335.
Dunn, E. R. 1926. Salamanders of the Family Plethodontidae. Smith College, Northampton, MA. 441p.
Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press. xvi + 587p.
Sessions, S. K., and J. Kezer. 1987. Cytogenetic evolution in the genus Aneides. Chromosoma 95:17-30.
Staub, N. L. 1993. Intraspecific agonistic behavior of the salamander Aneides flavipunctatus (Amphibia: Plethodontidae) with comparisons to other plethodontid species. Herpetologica 49:271-282.
Stebbins, R. C. 1951. Amphibians of Western North America. University of California Press, Berkeley. ix + 539p.