Black-bellied slender salamanders probably consume similar prey. B. nigriventris usually does not excavate burrows. Eggs have been found in communal sites beneath rocks, boards, and in pockets of soil near the surface. In dry weather, these salamanders retreat underground.
Surface activity is limited by extremes in temperature and unfavorable moisture conditions.
Eggs have been found from November 5 to March 14. Hatchlings emerge during winter and early spring. Potential predators include spotted and striped skunks, raccoons, ringtails, gray foxes, ringneck snakes, and various skinks, moles, and shrews. Los Angeles Co. Mus. Hendrickson, J. R. 1954.