This salamander is much lighter in color than a typical Arboreal Salamander. Other typically colored salamanders were found near it. It could be missing some of its melanin or dark pigment, or its appearance could be a result of the salamander changing its color, which was described by Robert Stebbins. See description below.
During the dry period, usually from May or June to October or November, Arboreal Salamanders hide out in cool moist areas, usually underground, sometimes in tree hollows, sometimes in basements and underground garages.
Female Arboreal Salamanders lay their eggs in a moist place in late Spring or early Summer, and typically remain with the eggs until they hatch in August and September, shortly before the onset of the Fall rains which allow them to come out of hiding. These eggs were found with several aestivating Arboreal Salamanders in late July under some old redwood planks in a shaded area next to a house in Sonoma County.
Arboreal salamanders inhabit
rocky Año Nuevo Island.
A careful look underneath the fallen branches and bark of the dead tree shown above on a wet winter afternoon turned up 16 salamanders of 4 species - one Arboreal Salamander, two Coast Range Newts, one Yellow-eyed Ensatina, and 12 California Slender Salamanders, proving that wood debris on a forest floor is an important microhabitat for salamanders. Along with fallen debris, tree bark, tree cavities, root holes, and splits in trees are also useful habitat for many kinds of wildlife, including birds, mammals, amphibians and reptiles, but dead trees and their debris are often removed indiscriminately without consideration for wildlife.
An Arboreal Salamander, found sitting out on a rock at night, chirps when I grasp it across the sides firmly with my thumb and one finger. The salamander was not squeezed so hard that the sound was just the sound of air being pushed out of its lungs. This species is capable of making a fairly loud sound, but this one was very quiet, so there is a lot of background noise from a flowing creek nearby.
Adults measure 2 1/4 - 4 inches long (5.7 - 10.1 cm) from snout to vent and up to 7 inches (18 cm) in total length. The largest species of Aneides.
A medium sized lungless salamander.
Toe tips are expanded and squarish.
Tail is semi-prehensile, often seen coiled.
Usually 15 costal grooves.
Two nasolabial grooves.
Color and Pattern
Color is brown above with small cream to yellow spots.
The number and size of the spots varies with location - Most Sierra Nevada and North Coast populations have weak spotting, while Gabilan Mountains and Southeast Farallon Island populations have large conspicuous spots. Other areas have populations with small spots and populations with intermediate spots.
The venter is creamy white.
The undersides of the tail and feet are dull yellow.
On page 129 of his 1962 book "Amphibians of North America, Robert Stebbins writes that Aneides lugubris is:
"Capable of marked color change. When kept in a dark, cold room at 12 degrees C., 6 adults were dark-colored, with the dorsal light-colored cloudings obscure. In the laboratory at 21 degrees C., where well illuminated, the light-colored markings of the animals became conspicuous, almost dominating the dark ground color. The changes evidently are achieved principally by changes in the melanic pigmentation."
Male / Female Differences
Males have broader, more triangular heads than females.
Young are dark, clouded with gray or brassy color.
Life History and Behavior
A member of family Plethodontidae, the Plethodontid or Lungless Salamanders.
Plethodontid salamanders do not breathe through lungs. They conduct respiration through their skin and the tissues lining their mouth. This requires them to live in damp environments on land and to move about on the ground only during times of high humidity. (Plethodontid salamanders native to California do not inhabit streams or bodies of water but they are capable of surviving for a short time if they fall into water.)
Plethodontid salamanders are also distinguished by their naso-labial grooves, which are vertical slits between the nostrils and upper lip that are lined with glands associated with chemoreception.
All Plethodontid Salamanders native to California lay eggs in moist places on land.
The young develop in the egg and hatch directly into a tiny terrestrial salamander with the same body form as an adult.
(They do not hatch in the water and begin their lives as tiny swimming larvae breathing through gills like some other types of salamanders.)
Active when soil moisture is high after the onset of fall rains, usually in November, to May, but relatively tolerant of dry conditions compared to many other salamander species.
Strong jaws and sharp teeth are capable of producing a painful bite.
Adapted for climbing with long toes and rounded semi-prehensile.
Has been found up to 59 ft. (18 m) above the ground.
Both males and females are agressively territorial. Individuals covered with scars (probably from fighting) are often found, and captives kept together often bite the other salamander's tail. Since the species is often found sheltering together in large numbers in dry weather, it appears that this territorial agression is not constant.
Anti-predator behaviors include biting, a raised defensive posture, making a squeaking sound, fleeing rapidly, and jumping.
This salamander may squeak when it is picked up or disturbed.
(Here's a recorded example - There's a faint high-pitched squeak, then some rustling background noise, then another faint squeak.)
According to Stebbins and Cohen, 1997, an Arboreal Salamander "...may squeak repeatedly when caught, retracting its eyes into their sockets each time a sound is produced, When the eyeballs are depressed, their undersides protrude into the mouth cavity, thereby compressing the air in the mouth and forcing it outward. It is this movement that appears somehow to cause the sounds produced."
Diet and Feeding
Eats a variety of small invertebrates including millipedes, worms, snails, ants, termites, sowbugs, moths, and centipedes.
Also known to eat slender salamanders (Batrachoseps.)
Prey is captured by the tongue and brought into the mouth where it is crushed.
A sit-and-wait-predator, adults forage for small invertebrates and sometimes slender salamanders on the ground at night during wet weather.
Reproduction is terrestrial.
Adults probably reach sexual maturity in their third year.
I have not yet found any documentation that describes the time of year when this species breeds, but it is most likely during late winter and early spring, since eggs are laid in late spring to early summer.
Breeding males have a heart-shaped mental gland under their chin. Males put this gland on a female's back, stroking her back quickly with it during courtship while scratching her skin with his teeth to deliver the mental gland pheromones to the female.
In late spring and early summer, females lay from 5 - 24 eggs in moist places, most commonly in decaying cavities of live oak trees, sometimes high off the ground, and also under rocks and other surface objects and inside logs.
Females usually remain with the eggs until they hatch, often coiled around them.
Sometimes the eggs of several salamanders are found together in large masses.
Males have also been found with females at the egg deposition site and adults and juveniles may stay together after hatching, perhaps waiting for the onset of the fall rains which will allow them to disperse from their refuge.
Young develop completely in the egg and hatch fully formed in August and September. (Staub and Wake in Lannoo 2005)
They may stay with the male and female for a time after hatching.
Lives in moist places on land, mostly in coastal oak woodlands, but also found in yellow pine and black oak forests in the Sierra Nevada and other dryer habitats, including coastal sand dunes. Also found on moist, mossy rock faces, under rocks and woody debris on land, inside stumps, and in urban yards and buildings. In Southern California, this salamander is also associated with sycamores along seasonal streams.
Endemic to California and northern Baja California.
Occurs from Humboldt county, south along the coast and coast ranges into Baja California del Norte, and in the foothills of the Sierra Nevada Mountains from El Dorado County to Madera County.
Also found on several islands off the coast of California - the Farallon Islands, Año Nuevo Island, and Catalina Island, and on Los Coronados Island off the coast of Baja California del Norte.
(The Santa Catalina Island record for this species is based on only one specimen found in 1941.
A three-year US Geological Survey biodiversity survey of the island failed to find any evidence of the species, suggesting that the single specimen was brought to the island from the Southern California mainland, probably with shipments of ranching materials, and it failed to establish a population.
From sea level to 5,000 ft. (1,500 m). (Stebbins, 2003)
Notes on Taxonomy
No subspecies are currently recognized, but two subspecies have been recognized in the past - Aneides lugubris lugubris - Arboreal Salamander, and Aneides lugubris farallonensis - Farallon Salamander or Farallon Yellow-spotted Salamander (found only on South Farallon Island).
DNA studies have shown that there are genetically different groups within the species. Sean B. Reilly et al ** in a study of the phylogeographic history of Aneides lugubris published in 2015 found substantial genetic diversity in the species due to historical isolation of populations. Their summary of the results and their conclusions are reproduced below (emphasis mine), and a copy of one of the maps from the paper can be seen by clicking on the range map below, all permitted under a Creative Commons license. The entire paper is available online at biomedcentral.com.
"Results: We found six major mitochondrial clades in A. lugubris. Nuclear loci supported the existence of at least three genetically distinct groups, corresponding to populations north of the San Francisco Bay and in the Sierra Nevada, in the Santa Cruz Mountains, and in the central coast and southern California. All of the genetic breaks in mitochondrial and nuclear loci corresponded to regions where historical barriers to dispersal have been observed in other species. Geologic or water barriers likely were the most important factors restricting gene flow among clades. Climatic unsuitability during glacial maximum may have contributed to the isolation of the mitochondrial clades in the central coast and southern California. A projection of our species distribution model to a future scenario with a moderate amount of climate change suggests that most of the range of A. lugubris will remain climatically suitable, but climatic conditions in the Sierra Nevada and low elevation areas in Southern California are likely to deteriorate."
Conclusions: Aneides lugubris contains substantial cryptic genetic diversity as a result of historical isolation of populations. At least two (and perhaps three) evolutionarily significant units in A. lugubris merit protection; all six mitochondrial clades should be considered as management units within the species."
Below is a map I made showing my estimates of the ranges of the 6 clades of A. lugubris, extrapolated from the map included in the publication. Areas where I am in doubt which clade is present I have marked with gray. Approximate locations of the samples used on which I based the shaded portions of the map are shown as darker dots. Click on the map below to see the original map from the publication.
Estimated ranges of the 6 clades of Aneides lugubris (Gray = clade uncertain.)
** Sean B. Reilly, Ammon Corl, and David B. Wake. An integrative approach to phylogeography: investigating the effects of ancient seaways, climate, and historical geology on multi-locus phylogeographic boundaries of the Arboreal Salamander (Aneides lugubris). BMC Evolutionary Biology (November 2015) 15:241.
"There are two geographically segregated groups of chromosomally differentiated populations of arboreal salamanders (Sessions and Kezer, 1987). These two karyotypes intergrade in south and east-central Mendocino County (Sessions and Kezer, 1987). Unpublished genetic analyses (allozymes and mitochondrial DNA sequences) show that the chromosomal units do not correlate with patterns of genetic variation (Jackman, 1993). The Farallon Island population is most similar genetically to the nearest mainland population, not populations in the Gabilan mountains to the south as suggested by Morafka (1976; see also Jackman, 1993)."
Nancy L Staub and David B. Wake. Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005.
The Arboreal Salamanders on Southeast Farallon Island were recognized previously as the subspecies A. l. farallonensis - Farallon Salamander (Morafka, 1976), because they are more heavily spotted than mainland salamanders (except for those found in the Gabilan Mountains of Monterey County.) They have since been found to be similar genetically to the nearest mainland populations.
Alternate and Previous Names (Synonyms)
Stebbins, Robert C., and McGinnis, Samuel M. Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.
Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.
Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.
Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.
Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.
Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.
Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.
Bishop, Sherman C. Handbook of Salamanders. Cornell University Press, 1943.
Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005.
Petranka, James W. Salamanders of the United States and Canada. Smithsonian Institution, 1998.
Storer, Tracy I. A Synopsis of the Amphibia of California. University of Califonia Publications in Zoology Volume 27, The University of California Press, 1925.
Jones, Lawrence L. C. , William P. Leonard, Deanna H. Olson, editors. Amphibians of the Pacific Northwest. Seattle Audubon Society, 2005.
Stebbins, Robert C. and Nathan W. Cohen. A Natural History of Amphibians. Princeton University Press, 1997.
David J. Morafka. Biogeographical Implications of Pattern Variation in the Salamander Aneides lugubris. Copeia, Vol. 1976, No. 3 (Aug. 20, 1976), pp. 580-586.
Robert Cyril Stebbins. Amphibians of Western North America, University of California Press, 1962.
The following conservation status listings for this animal are taken from the November 2020 California "Special Animals List" and the November 2020 "State and Federally Listed Endangered and Threatened Animals of California" list, both of which are produced by multiple agencies and available here: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. You can check the link to see if there are more recent lists.
If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can go to the NatureServe and IUCN websites to check their rankings.
This salamander is not included on the Special Animals List, meaning there are no significant conservation concerns for it in California according to the California Department of Fish and Game.