Amphibians
Slender Salamander
Batrachoseps · also called worm salamander, California slender salamander
Turn over a damp log in a California garden in winter and you may find what looks like a small earthworm — until it winds itself into a tight coil and then, if you keep watching, flings itself away. That is a slender salamander, one of the strangest-shaped amphibians in North America.
Overview
Batrachoseps is a genus of more than 20 species in western North America, most of them in California and Oregon. They have very long, narrow bodies, deeply grooved sides, and tiny four-toed feet — the shape that earns them the name “worm salamander.” They eat springtails, mites, and other minute arthropods.
No lungs, no pond
Slender salamanders are lungless, breathing through moist skin, and they lay eggs in damp soil that hatch straight into small salamanders — no tadpole, no standing water. That lets them live in dry coastal California, active only in the rainy season and sealed underground through summer.
Coil and spring
Cornered, the salamander winds into a flat spiral like a watch spring. Pushed further, it can unroll explosively, bouncing itself clear, and it drops its thrashing tail as a decoy.
A genus that keeps growing
Because these salamanders barely move and cannot cross dry ground, hillside populations become isolated and slowly split into new species that still look identical. Genetic work keeps adding to the count.
Status
Most slender salamanders are Least Concern and common, even in gardens. A few narrow-range species, such as the Kern Canyon and desert slender salamanders, are threatened.
Slender Salamander: common questions
I found what looks like an earthworm with legs. Is it a slender salamander?
Very likely, if you are in California or the Pacific Northwest and it was under a log, a board, a plant pot, or leaf litter in the cooler, wetter months. Slender salamanders are the amphibian most often mistaken for worms. Look closely for four tiny legs, a distinct head with eyes and nostrils, and a groove pattern down the sides; an earthworm has none of these and its body is ringed all the way around. The salamander will also usually coil up or thrash when uncovered, while a worm just contracts. Replace the cover gently and the animal will be fine.
How does a salamander with no lungs breathe?
Through its skin and the lining of its mouth and throat. Oxygen dissolves into the film of moisture on the skin surface and passes straight into a dense network of blood vessels just underneath, and carbon dioxide leaves the same way. This works only while the skin stays wet, which is why slender salamanders are found in damp microhabitats, are active mainly on rainy or dewy nights, and disappear underground when the surface dries out. The whole lungless salamander family, the largest salamander family in the world, breathes this way.
Why are there so many species of slender salamander?
Because they barely move. A slender salamander may spend its entire life within a few metres of where it hatched, it cannot cross dry ground or open habitat, and it does not disperse far even over generations. Populations on separate hillsides, on opposite sides of a valley, or in different patches of forest become genetically isolated and, over long periods, diverge into distinct species that still look almost the same. Genetic studies of California Batrachoseps keep splitting what were thought to be single wide-ranging species into several, and the count is still rising.
Are slender salamanders dangerous or poisonous?
Not to people. Like many lungless salamanders they produce mild skin secretions that make them distasteful to some predators and can sting if rubbed into the eyes, but they cannot bite hard enough to matter and carry nothing dangerous to a person. The usual amphibian handling rules apply, and matter more here than for you — their thin skin is easily harmed by the salts, oils, and lotions on human hands, so a quick look with clean, wet hands and a careful return to cover is the right approach.