This is the simplest method to distinguish B. major from the similar B. nigriventris where the two co-occur, although the latter is typically also much smaller and less robust.

In the northern part of its range in Los Angeles County, B. major is restricted to low elevation valleys and basins.

Native habitat for B. major includes coastal sage scrub, oak woodland, conifer forests, and, rarely, north-facing slopes of desert mountains in the Peninsular ranges.

[3] In the northern part of its range, B. major often co-occurs with B. nigriventris, sometimes being found underneath cover side-by-side.

B. m. aridus occupies limestone seeps with permanent water shaded by California fan palms, enabling its survival in a dry environment otherwise completely inhospitable to salamanders.

[1] B. major is able to adapt to dramatically human-altered habitats, such as suburban yards,[5] to a greater extent than most other local amphibians, and as such is able to inhabit urban areas[3] where other native wildlife has been wiped out.