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Batrachoseps attenuatusCalifornia Slender Salamander

By Harry Bicknell; Sanya Cowal; Allie Saunders

Geographic Range

Batrachoseps attenuatus can be found from Central California northward through southern Oregon. On the southern end of their geographic range, they are widespread in northern California in Santa Cruz, Santa Clara, and San Benito Counties. On the northern end, they are present in a narrow strip along the coast on the south side of the Rogue River in Oregon. However, their range north of San Francisco Bay is restricted towards the coast (Jones et al, 2005). (Jones, et al., 2005)

Habitat

California slender salamanders live in many habitats, including chaparral, coniferous forests, interior live oak woodlands, and coastal scrubland. However, in the north of their geographic range, they can be found in grasslands under isolated trees or in mature and old-growth forests . Overall, they are found in low–elevation humid coastal regions. They are easily located underneath logs and rocks during wetter months, and can be found in urban areas, such as in house gardens. During dryer months, they burrow (Jones et al, 2005; Nussbaum et al, 1983; Petranka, 1998). (Jones, et al., 2005; Nussbaum, et al., 1983; Petranka, 1998)

Physical Description

Batrachoseps attenuatus is easily distinguished from other northwest American salamanders because of its extremely elongated body, short limbs, and very small digits. This salamander appears worm-like with a dark brown to black ground color, and a reddish-brown, buff, or yellowish dorsal stripe. This dorsal stripe may be light or completely missing in older adults. However, there can be much variation in individual coloring, with the dorsal stripe presenting as reddish brown, red, gray, pinkish gray, or dirty yellow. Its venter is slate grey with a fine, white stippling. Furthermore, it only has four toes on each of its two hind limbs, and has a tail that is significantly longer than the length of both its head and body combined. The tail often makes up 55–65% of the total body length. The number of costal grooves and intercostal folds stated varied by source. This salamander has between 18 and 22 costal grooves, where 20–21 is most common. It has 10 to 13 intercostal folds between the tips of toes. Adult body size ranges from 45 to 55 mm SVL; at its smallest this salamander is 20 mm SVL and at largest 138 mm SVL. Sexually active males can appear to have swollen snouts or enlarged premaxillary teeth, but besides these indicators, there is no sexual dimorphism (Nussbaum et al, 1983; Jones et. al, 2005; Pentranka, 1998). (Jones, et al., 2005; Nussbaum, et al., 1983; Petranka, 1998)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    45 to 138 mm
    1.77 to 5.43 in
  • Average length
    50 mm
    1.97 in

Development

Juveniles measure 14-19 mm TL when hatched and grow anywhere from 3–6 mm SVL/year, but the growth rate declines to 1–3 mm SVL/year once sexually mature. However, body size is not always a good predictor of age, because adult body size can range from between 34 to above 40 mm SVL. This species becomes sexually mature between 2–4 years old (Petranaka, 1998). (Petranka, 1998)

Reproduction

Information about the courtship behavior of this species is unknown (Jones et al, 2005). (Jones, et al., 2005)

Mating season for California slender salamanders occurs during fall rains during the months of October and November. Males and females mate both above and below the surface, during dry seasons the California slender salamanders mate in damp areas, typically underground. Females lay eggs that are coated in a jelly that both protects the eggs, and allows them to remain close together. There is little contact between males and females during the reproduction process. This is further evidenced by the lack of adult salamanders in nesting areas after the laying of eggs (Jones et. al, 2005). (Jones, et al., 2005; Petranka, 1998)

  • Breeding season
    October- November
  • Range number of offspring
    21 to 74
  • Average number of offspring
    53
  • Range time to hatching
    79 (high) days
  • Average time to hatching
    64 days
  • Average time to independence
    1 years
  • Average age at sexual or reproductive maturity (female)
    3.5 years
  • Average age at sexual or reproductive maturity (male)
    2.5 years

Males are very defensive of their nests against other males. (Jones, et al., 2005)

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth
    • protecting
      • male

Lifespan/Longevity

California slender salamanders can live from 1 year up to 8 years. Males are thought to mature at 2.5 years of age and females mature at 3.5 years of age. Aging studies have shown that California slender salamanders can be at least 8 years old, but it is possible that they can grow beyond that age. In addition to having lengthy lives, California slender salamanders can regenerate limbs. If they are attacked by a predator, they are able to regrow limbs lost during attacks. This typically ends up being their tails, however it allows them to continue living normally even after lie threatening attacks (Jones et. al, 2005). (Jones, et al., 2005)

  • Average lifespan
    Status: wild
    8 years
  • Typical lifespan
    Status: wild
    1 to 8 years
  • Average lifespan
    Status: wild
    3.5 years

Behavior

California slender salamanders enjoy wet ecosystems they surface from under logs and wooded areas, when the topsoil is wet. They spend the majority of their life in the same area measuring 1.5 meters long. When the climate begins to become more hot and dry, they will burrow underground until the topsoil becomes wet again. Another behavior that is noted, is that they take care of themselves before it cares to have offspring. This is evidenced by females regenerating their tails, rather than laying eggs. When they regenerate their tail, it makes them miss the mating season and they must wait another year to lay eggs. When feeding, California slender salamanders often stay motionless and wait for their prey to come near them so they can sneak up on it. However in salamander dense areas, if prey is present California slender salamanders fight and can be aggressive to each other (Petranka, 1998). (Petranka, 1998)

Home Range

California slender salamanders primarily reside in the Sierra Nevada mountains from Central California to Southern Oregon. They are also known to live on the Northern California Coast. They live in a variety of different ecosystems such as grasslands, chaparral, and coniferous forests (Petranka, 1998). (Petranka, 1998)

Communication and Perception

Chemical communication exists among California slender salamanders. Research suggests that the salamanders may use scent marking to differentiate between their territory and the territories of other salamanders. Communication during courtship is unknown (Olson, 2008; Petranka, 1998). (Olson, 2008; Petranka, 1998)

Food Habits

This salamander spends much of its time underground but forages on the surface of the ground for food. They have frequently been observed foraging in roadside banks. Their diet differs depending on location. In central california, they primarily eat snails, collembolans, mites, dipterans, aphids, and thrips. In northern california, they primarily feed on mites, springtails, small spiders, flies, and snails. They sit and wait for their prey, then capture it with with their quick tongue (Petranka, 1998; Jones et. al, 2005). (Jones, et al., 2005; Petranka, 1998)

  • Animal Foods
  • insects
  • mollusks

Predation

California slender salamanders are typically prey rather than predator. Because they spend most of their lives on the ground, it is susceptible to predation by larger arboreal salamanders, various types of snakes, primarily garter and ringneck snakes, and white footed mice. In order to defend itself from its predators the California slender salamanders have developed two different forms of defense and those include, wrapping itself into a tight coil, in which its head is under the coil and protected and just going motionless (Petranka, 1998). (Petranka, 1998; Petranka, 1998)

  • Known Predators
    • arboreal salamanders (Aneides species)
    • snakes (Serpentes)
    • white-footed mice (Peromyscus species)

Ecosystem Roles

California slender salamanders play an important role in regulating the amount of insects in the California woodlands.They eat many invertebrates as well as small insects, regulating the food chain of their ecosystem (Olson, 2008; Petranka, 1998). (Olson, 2008; Petranka, 1998)

  • Ecosystem Impact
  • creates habitat

Economic Importance for Humans: Positive

There are no known positive effects of California slender salamanders on humans. However, its function in the ecosystem regulates insects and it functions as prey for other species that humans benefit from.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of California slender salamanders on humans.

Conservation Status

Habitat loss is a known threat to California slender salamanders in California. Other possible threats across the full range of the species include disease and activities that alter habitat, such as timber harvest and natural disturbances such as fire. California slender salamanders are resilient and can persist in fragmented habitats. Climate change and the application of chemicals are also possible threats. More research must be conducted to understand the full extent of threats to this species (Olson, 2008). (Olson, 2008)

Other Comments

California slender salamanders are a common species. They produce toxic skin secretions, but research has not been conducted to determine whether these secretions are used to deter predators (Jones et. al, 2005; Petranka, 1998). (Jones, et al., 2005; Petranka, 1998)

Contributors

Harry Bicknell (author), Seattle University, Sanya Cowal (author), Seattle University, Allie Saunders (author), Seattle University, Gordon Miller (editor), Seattle University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

ovoviviparous

reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

suburban

living in residential areas on the outskirts of large cities or towns.

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

References

Jones, L., W. Leonard, D. Olson. 2005. Amphibians of the Pacific Northwest. Seattle, WA: Seattle Audubon Society.

Nussbaum, R., E. Brodie, R. Storm. 1983. Amphibians and Reptiles of The Pacific Northwest. Moscow, Idaho: University of Idaho Press.

Olson, D. 2008. "Conservation Assessment for the California Slender Salamander in Oregon." (On-line). U.S.D.A. Forest Service Region 6 and U.S.D.I. Bureau of Land Management Interagency Special Status and Sensitive Species Program. Accessed May 21, 2019 at https://andrewsforest.oregonstate.edu/sites/default/files/lter/pubs/pdf/pub4517.pdf.

Petranka, J. 1998. Salamanders of the United States and Canada. Washington, DC: Smithsonian Institution Press.

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