While the range of the brown smoothhound extends from northern Oregon to Peru, it is rare south of the Gulf of California and is considered common only north of Monterey bay with historically abundant populations in San Francisco, Tomales and Humbolt bays. Brown smoothies or brownies look very similar to gray smooth hounds in shape and build but are of a much darker reddish brown to blackish brown coloration with a larger spiracle than the gray smoothy. Like the gray smoothy, the brown smoothy inhabits shallow coastal waters, often foraging just out side the breakers. It is common in tidal flats and around oyster beds, where it feeds on crabs, shrimp, and small fishes.
Reproduction is viviparous.
Pups are several inches long.