ANIMAL ESTATE client 5.1: California Slender Salamander
FROM ANIMAL ESTATES 4.0: SAN FRANCISCO, CA
SCIENTIFIC NAME: Batrachoseps attenuatus
ANIMAL PROFILE: California slender salamanders are members of the plethodont family. They have no lungs, and breathe entirel y through their skin. They are completely terrestrial and undergo no aquatic larval stage (babies are mini short-tailed, long-legged, and large-headed replicas of the adults). They have four toes on front and hind feet. All slender salamanders have "many teeth" as is implied by the definition of their family name. Males have a broader squarish snout and projecting upper premaxillary teeth (which are used in mating). Like all plethodonts, slenders have a nasolabial groove extending from each nostril to the upper lip; these aid in picking up chemical information from the environment and are believed to play a part in salamander communication.
California Slender Salamanders average from 3 to 5 1/2 inches in length (1 1/4" to under 2" snout to vent). Tails may be twice as long as snout to vent length, especially in males. Adults are short-limbed and very worm-like; it takes a while for the juveniles' bodies and tails to outgrow the proportions of their heads and legs. Everything becomes elongated. Thus the nomenclature "slender". Slenders live 7 - 10 years. Prey consist of small insects (especially springtails and small beetles), snails, isopods, mites, and spiders, captured by a projectile tongue.
Although they are not aquatic, plethodonts do need consistently moist living conditions. They are active on rainy or wet nights when temperatures are moderate, beginning with the first fall rains until the spring or summer dry period, when many salamander species aestivate (summer "hibernation") and are more difficult to find as they seek deeper shelter. Slenders retreat underground when the soil dries or when air temperature gets below freezing. Lives and lays eggs in moist places on land. After mating, females deposit 5-20 rather large eggs (compared to their body size), surrounded by capsules and connected by chords of jelly in rosary like chains. Although females may be nearby, they don't active brood the eggs. The youngsters hatch in about two months. Space is often shared with one of the their plethodont cousins - the ensatina, in large communal nests.
RANGE: California slender salamanders occur in two principal areas: along the California coast and adjacent Inner Coast Ranges from north and east of Monterey Bay (extreme western Merced, Monterey, and San Benito counties) northward to extreme southwestern Oregon (south side of the Rogue River, Curry County); and in the western foothills of the northern and central Sierra Nevada, from Calaveras County north to at least Butte County.
HABITAT: From fall to late spring or sum mer Slenders can be found under logs, bark, rocks, boards, and other surface cover, and in damp leaf litter. California Slenders inhabit variable terrains that include w oodland, forest (esp. redwood), chaparral, grasslands scattered with trees, as well as yards and vacant lots.
THREATS: Predators include sharp-tailed snakes, Santa Cruz garter snakes, California giant salamanders, and scrub jays. Slender salamanders have a unique defensive behavio r. Besides slinking into tight crevices, when threatened, slenders will coil and use t heir tails as a spring so as to "catapult" themselves out of an enemy's grasp. This more than not resembles the frantic antics of a wriggling worm. As a last resort, if the tail is caught, slender salamanders are capable of caudal autonomy - meaning their tales can detach from their bodies. Other anti-predator techniques include immobility/crypsis and the release of adhesive skin secretions.
INTERESTING FACTS: Slender salamanders are an ancient lineage. They are entirely sedentary and in their entire lifespan an individual may move no more than a few square yards. This means that slender salamanders -- perhaps more than any other type of vertebrate -- are simply "riding" the underlying tectonic plates. / Of the more than ten species of Batrachoseps in California, B. attenuatus is the only one found in the greater San Francisco Bay Region.
MAKING A SALAMANDER BOARD: Simply placing an untreated, pine shelving board (1ft by ft) flush with the ground under the leaf litter in each plot and the duff replaced over the boards can attract salamanders to your garden. Essentially the wooden board/log serves as the roof for the salamander home, and function as surrogate logs.
PRBO Conservation Science
Alleghany Institute of Natural History
by Michelle Koo, California Academy of Sciences, for the Animal Estates 4.0 Field Guide
One of the first amphibian species to be scientifically described from the San Francisco Bay Area (in 1833), the California Slender Salamander continues to be a part of our landscape. It is also likely to be one of the Bay Area's oldest amphibian species having thrived in the region and coastal California much before the Bay was even formed. Its natural history traits that has allowed it to persist in a dramatically changed region through thousands of years continues to serve this diminutive amphibian well as it continues to live in urban and suburban habitats.
The California Slender Salamander, scientifically known as Batrachoseps attenuatus, is a small, elongate salamander, with large eyes on a blunt head and very thin limbs ending in four dainty toes. Its overall color is dark brown to dark gray with a paler belly; in a healthy adult, yellow tinges of fat or light-colored eggs can be seen through its slightly translucent undersides, which are speckled with fine white spots. Up to 5 or 6 inches long, its tail is often one and half times longer than its body. Grooves along its back and tail lend a segmented appearance, not unlike a 'worm' that a casual observer might mistake it for. Their antiquated English name of 'worm salamander' comes from this mistaken identity. A broad stripe of speckled color down its back continuing through its long tail may be dark brick red, brown, buff or tannish yellow, and it is common to see in a single group of Slender Salamanders many variations of color.
This salamander is part of a large family of amphibians known as the Lungless Salamanders (Plethodontidae), which uses its thin, permeable skin to breathe. Because of this, California Slender Salamanders must stay moist at all times. They live in damp leaf litter of forests, oak woodlands and grasslands, staying hidden underneath rotting logs or in the humus of the forest floors and in grassland thatch. The center of their range is the San Francisco Bay Area and extends east to the chaparral of the Sierra Nevada foothills and north and south along the coast in Redwood or Coastal Oak forests until just north of the Oregon border and just south to about Monterey Bay. When it becomes too hot and dry or the temperatures drop to freezing, they retreat to underground crevices following tree roots and earthworm tunnels or seek out the deep moist centers of fallen trees. California Slender Salamanders resurface during the cool rains of fall, but studies have shown they do not migrate far, doubtless if all their needs are met. They feed on small insects, such as springtails, small bark beetles, crickets, young snails, mites, and spiders. Like all salamanders in this family, they use their projectile tongue to grab their prey in a flash.
California Slender Salamanders are tolerating of their surroundings as long as key considerations are met. A suitable urban backyard habitat needs both perennials and shrubs, maybe a tree to capture San Francisco's fog dew, with deep layers of organic matter. Cover objects, such as stepping stones, logs, even a statuette, all create moist retreats from predators and their deadliest limitation of drying out. They have few specific requirements of an urban gardener except well-planted areas with cover that are lightly disturbed. You may find them in your backyard compost heaps fattening up on fruit flies and spiders, or under the mat of moss scraped off a brick walkway. A well-planted, organic garden that is not overly manicured (perhaps leave last year's fallen leaves to compost on the ground) suits them well.
The natural predators of California Slender Salamanders are garter snakes (e.g. Thamnophis elegans, T. atratus), Sharp-tailed snakes (Contia tenuis), large salamanders such as Giant Pacific Salamander (Dicamptodon) and probably the Arboreal Salamander (Aneides lugubris). Birds are also known to eat Slender Salamanders, such as Scrub jays (Aphelocoma coerulescens) and the occasional backyard chicken. California Slender Salamanders, for the most part, exhibit a mellow if not somnolent character; however, to see one spring from its coil or flip violent around, both behaviors appear appropriate anti-predator tactics. If hiding in the leaf litter doesn't work, then a surprise flip in a new attempt to blend back into the surroundings, remaining motionless, may avoid an unpleasant end. More extreme measures include breaking off its tail (don't worry, they grow back) and secreting sticky mucus from its skin to deter would-be diners.
They can be encountered in surprisingly large numbers; a single overturned stone can have dozens. It is common to find variation in colors and in sizes depending on the time of year with newly hatched young curled up next large adults. In larger parks and in more varied habitats, California Slender Salamanders may also be found with their larger, flashier, lungless cousins, the Arboreal Salamander (Aneides lugubris) and Ensatina (Ensatina eschscholtzii). The Arboreal Salamander is a muscular-looking creature, males having large triangular heads, often showing an overbite of large impressive teeth. Ensatina in the San Francisco Bay Area are bright orange overall with golden highlights on the upper half of its eyes.
An important part of the California Slender Salamander's natural history that is common to most lungless salamanders is their independence from standing water. Unlike other amphibians in California, such as frogs, Slender Salamanders do not lay their eggs in water and hatch into tadpoles. Instead they lay eggs in underground burrows or in logs where they hatch into miniature versions of their adult form, foregoing metamorphosis and thus dependence on standing water, a direct developer. The white, spherical eggs are less laid than attached to the roof of the nest site by a strong gelatinous stalk, completely self-contained with embryo, yolk and successive layers of tough and viscous jelly. California Slender Salamanders are known to lay their eggs in communal nests, sometimes up to 60 - 70 eggs, the likely combined contribution of at least 7 to 10 females. Females have been found with these communal nests but no parental care is given.
With such abundance possible, it's a wonder we miss seeing them. Their cryptic habits defy our understanding of fundamental questions we have about how they interact with each other. What is courtship like between California Slender Salamanders? Do females actively seek out communal egg nests, or is it largely circumstance that they all choose to lay eggs in the same hidden nook? Are they guarding eggs when we find them in association with communal egg nests? And if so, against what? Do they fight over food, or the best retreats, or resolve them in other ways suitable to a low energy animal? Do they have territories? Where do the young go? Where do the old and infirmed go?We do know that where once it was thought there was one species of highly variable Slender Salamanders, we actually have up to 19 distinct species of Slender Salamanders in California, most likely more. They are more complicated than we thought. We also know with California's real estate being as highly valued as it is, the biggest threat to the Slender Salamander is continuing habitat loss across the state and in the San Francisco Bay Area. Fortunately, the California Slender Salamander is also tolerate of human-created habitats and can appear in abundance in small patches, such as an urban backyard. If you are lucky to find Slender Salamanders in your yard, you will likely see the same ones every rainy season; in the spring, if you find little ones, you'll know you've been doing well.