Desert Slender Salamander

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Desert Slender Salamander

Batrachoseps aridus

ListedJune 4, 1973
FamilyPlethodontidae (Lungless Salamander)
DescriptionReclusive, nocturnal salamander.
HabitatDesert canyons; fractures in limestone walls.
ReproductionEggs laid between November and Jauary.
ThreatsLow numbers, limited distribution.


The desert slender salamander is an anatomically primitive member of its genus, measuring less than 4 in (10.2 cm) from the snout to the tip of the tail. It has four toes on each foot and a large rounded head. It is dark maroon to deep chocolate with numerous tiny silvery blue spots and scattered large patches of gold. The belly is dark maroon, and the tail a contrasting flesh color. This salamander was discovered and described as a new species in 1970.


The reclusive desert slender salamander spends most of its life within porous-soil, bedrock fractures, or limestone sheeting, where groundwater seepage provides moisture. Occasionally found under loose rocks by day, the salamander is most active at night. When disturbed, it winds itself up into a watch-spring-like coil.

This salamander stalks and eats small invertebrates, with flies and ants making up the bulk of its diet. The influence of season, temperature, moisture, food supply, predation, and breeding on the salamander's surface activity and population size are largely unknown. Little is known about the salamander's breeding habits. Females probably lay eggs between November and January soon after the first heavy rains of winter.


This salamander lives in an arid region of low and erratic rainfall, high summer temperatures, and strong spring winds. Seasonal watercourses between steep canyon walls of igneous and metamorphic rock are found above and below the limestone strata inhabited by the salamander. Exposed bedrock, talus, and coarse-grained sand form surface material on surrounding slopes. The sparse plant community, typical of a desert oasis, consists of fen palm, narrow-leaved willow, squaw-waterweed, stream orchid, maidenhair fern, and sugarbush.


Because it was so recently discovered, little information is available on the historical distribution of the desert slender salamander. It has been found only on the lower slopes of the Santa Rosa Mountains in Riverside County in southern California. Because of its isolation from other members of the genus and its primitive characteristics, scientists surmise that the slender desert salamander is a relict species that was more widespread during earlier, wetter geological epochs.

The desert slender salamander is known from two locationsHidden Palms Canyon and Guadalupe Canyon. Hidden Palms Canyon is at the box end of Deep Canyon, a large gorge that drains the surrounding slopes of the Santa Rosa Mountains. The inhabited area is less than an acre and supports fewer than 500 individuals. The Guadalupe Canyon population appears much smaller in range and numbers, consisting of perhaps 100 individuals, but this site has not been closely studied.


The major threat to the survival of this salamander is its extremely restricted distribution. This makes the species particularly vulnerable to any natural catastrophe. For example, unusually severe rainfall and flooding associated with a tropical storm in 1976 caused the erosion and collapse of a limestone wall that made up as much as one-third of the salamander's habitat at Hidden Palms. At the other extreme, an extended drought could dry up groundwater seepage, rendering the species extinct. Human activity in the area is slight.

Conservation and Recovery

Land surrounding both populations, comprising about 138 acres (55 hectares), was acquired by the state of California in 1973. The following year, this tract was established as the Hidden Palms Ecological Reserve, managed by the California Fish and Game Commission. After the flooding of 1976, the rock wall of the Hidden Palms habitat was reinforced to prevent any further collapse. Boulder barricades were constructed to restrict unauthorized access to both canyons. The management plan for the reserve will consider other steps as needed to stabilize the habitat or to discourage human disturbance.


U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Ave.
Portland, Oregon 97232-4181
Telephone number:(503) 231-6121


Brame, A. H. 1970. "A New Species of Batrachoseps (Slender Salamander) from the Desert of Southern California." Los Angeles County Museum Contributions to Science No. 200.

U. S. Fish and Wildlife Service. 1982. "Desert Slender Salamander Recovery Plan." U. S. Fish and Wildlife Service, Portland.