[1] N. emarginata is a rocky intertidal gastropod carnivore that feeds on a variety of sessile and sedentary species such as barnacles, mussels, and limpets.

[3][4][5] When drilling, it alternates acid secretions with scraping by its radula until it has fully penetrated the prey's shell, leaving a characteristic hole about 1 mm in diameter.

[5] The speed of this process likely depends on temperature,[6] and the size of the hole depends on the size of the dogwhelk's accessory boring organ, which is generally larger in larger dogwhelks.

[8] Formerly known as N. ostrina, the two species were differentiated based on shell morphology, reproductive compatibility, and genetic sequencing in 1990.

[8] N. emarginata is now known to be distributed between Fort Point, California and Pacific Mexico.