Amphibians
Black-Bellied Slender Salamander
Batrachoseps nigriventris · also called black-bellied slender salamanders
Lift a damp log in a California coastal forest and a black-bellied slender salamander might slip away through a gap barely wider than its own head, a body built almost entirely for squeezing through spaces other animals cannot reach.
Overview
The black-bellied slender salamander, Batrachoseps nigriventris, is a thread-thin, lungless salamander native to forest habitat across California’s coastal mountain ranges and the southern Sierra Nevada foothills. Its extraordinarily slim build, dark underside, and lifestyle suited to tight underground spaces make it one of the more physically distinctive small salamanders in North America.
Built for the narrowest of gaps
Where most salamanders need at least a modest crevice to hide in, the black-bellied slender salamander’s remarkably thin body opens up spaces barely wide enough to notice, let alone squeeze through.
Status
Least Concern — widespread and common across suitable forest habitat throughout California’s coastal ranges and southern Sierra Nevada foothills.
Black-Bellied Slender Salamander: common questions
Why is the black-bellied slender salamander's body so thin?
This species has a notably thread-thin, elongated body even by the standards of its already slender genus, an adaptation that lets it squeeze into narrow rock crevices and soil gaps that would be completely inaccessible to bulkier salamander species.
How can you identify a black-bellied slender salamander?
Look for a distinctly dark, often near-black belly, a feature that helps distinguish this species from several paler relatives within the broader slender salamander genus found across California.
Does the black-bellied slender salamander have an aquatic larval stage?
No, like other members of its family, it has no lungs at all and lays eggs on land that hatch directly into fully formed miniature adults, skipping the aquatic larval stage entirely.
What does the black-bellied slender salamander do during the dry season?
This species retreats underground during California's dry summer months, emerging to be active mainly during the cooler, wetter parts of the year when moisture makes surface activity and foraging more viable.