One of several pacific northwest species of tidal snails called a Dogwinkle, the highly variable frilled Dogwinkle is different from other similar species, it has no grooved channels encircling the shell and the lack of colored bands like other snails. In sheltered areas, they commonly have a thin frill along the shell, but when growing in a wave swept beach, the frills are often missing.
This snail is a major predator of barnacles, feeding primarily on the acorn barnacle. It drills a hole in the prey using its teeth covered tongue and injects poison into the barnacle. The snail can then insert its tongue to scrape out the meat. Sometimes they are so prevalent that they limit the number of barnacles in a given area. They are preyed upon by the mottled and purple sea stars and the red rock crab.
The snail can be found from Alaska to central California in intertidal and shallow subtidal rocky areas of Vancouver Island.
The Frilled Dogwinkle can be found in winter or early spring along the low tide line. Females that are four or more years old will lay many yellow eggs about a 1 cm long that they attached to rocks. They lay their eggs in a communal nursery. A female can lay up to 1,000 eggs per year. After a month or so the young snails hatch by piercing the egg case, only about 1 percent survive to 1 year old.
In the spring and summer months, yellow egg cases can be seen attached to substrate on stalks, some call these sea oats. The sexes are separated, the male has a penis and the sperm is placed internally. After hatching, the larvae are free swimming.