This large, common intertidal species is negatively phototactic, so they are usually in crevices or on the underside of boulders during the day. It is commonly found on the roofs of sea caves. They come out to feed at night. It is one of the largest limpets that can be found in the intertidal here in the Pacific Northwest (though it does not get as large as the owl limpet, Lottia gigantea
, which is found further south). The white spots on the shell are translucent, and may be used to help the animal avoid bright light. The gut of this species often has a large parasitic protozoan, Eupoterian pernix
. This species can be found in brackish water. Predators include black oystercatchers, which capture many of them in the Rosario area, and crows, which may explain why they usually retreat to high up on vertical surfaces or under overhangs, in shaded places during the day. They are most common in the upper midlittoral so seastars and oyster drill snails are less likely to be a problem for them. They do not show an escape response to sea stars, as do some lower-living limpets such as the keyhole limpet Diodora aspera
. In California, spawning is in March and April.
The "persona" in the name refers to the dark stain on the interior of the apex, which sometimes looks like a mask or a person's face.
This limpet has the apex at the highest point of the shell and about 1/3 of the way back from the anterior margin. The apex is usually slightly inclined forward. The height of the shell is over 1/3 the width. The posterior and lateral slopes of the shell are convex, giving the shell an inflated profile. The inside of the shell is white with a large, dark apical blotch (photo) and a dark line or dark spots around the margin. The outline of the shell is oval, and the length is usually 1.3 times the width or more. There are no prominent ribs, though small, low ones may be present. The coloring is usually speckled and banded brown, greenish brown, or olive-green with tan or white speckles. Large, with length up to 5 cm, but usually about 3 cm.
Aleutian Islands to Isla Socorro, Mexico; less common south of Monterey Bay, CA