Lottia gigantea - Owl limpet

Geographic range:
Neah Bay, Washington to Bahia Tortugas, Baja California, Mexico

Key features:
Largest of the limpets (up to 10 cm across) on the central coast of California. Apex well forward of center and usually dark-light patterning along margin of shell.

Similar species:
Collisella pelta -- Shield limpet

Habitat(s):
bay (rocky shore), exposed rocky shore, protected rocky shore

Primary common name: Owl limpet		ITIS code: 69732
Synonymous name(s): Scurria gigantea
General grouping: Snails, limpets, abalone, chitons

Geographic Range
Range description: Lottia gigantea ranges from from Neah Bay, Washington to Bahia Tortugas, Baja California, Mexico.
Northern latitude extent: --		Southern latitude extent: --
East longitude extent: --		West longitude extent: --

Intertidal Height
Lowest intertidal height: 0 meters OR -1 feet		Highest intertidal height: 0 meters OR 5 feet
Intertidal height notes: Lottia gigantean is present in the high intertidal, especially in the southern part of its range. The largest specimens, however, are found in the middle zone, especially on surf-swept rocks.

Subtidal Depth Range
Minimum depth: 0 meters OR 0 feet		Maximum depth: 0 meters OR 0 feet
Subtidal depth notes: --

Habitats
Habitat(s): bay (rocky shore), exposed rocky shore, protected rocky shore
Habitat notes: Lottia gigantea lives in the rocky intertidal and are heavily exposed to heavy surf action. They are commonly found on bare rocks, cliffs and large boulders.

Abundance
Relative abundance: Lottia gigantea is scarce north of San Francisco with only a few found on the Oregon and Washington coasts.

Species Description
General description: Lottia gigantea is a solitary limpet in the class Gastropoda, comprising snails and slugs. Gastropoda is largest and most successful class in the phylum Mollusca. Lottia gigantea can grow much larger than other limpet species on the West Coast.
Distinctive features: The shell of Lottia gigantea is spotted brown and white but is often badly eroded. The inner surface of the shell is dark, the margin is brown, the side of the foot is gray and the sole of the foot is yellow to orange. There is an owl-shaped muscle scar in middle of inner surface and the apex is near the front end. The shell may have some radial ribs on it that are often worn and the margin is slightly scalloped.
Size: Lottia gigantea can grow to be 89 mm long, 70 mm wide and 32 mm high.

Natural History
General natural history: Lottia gigantea is territorial and at low tide occupy a characteristic home scar that fits precisely the margin of the shell. Around this home scar, they claim a territory of about 1000 square centimeters. Within this territory, they will bulldoze other species of limpets out and actively defend the area to keep other species from moving in. The absence of other species, combined with the nourishing mucus trail of Lottia gigantea, permits the rapid growth of a film of algae from spores that settle in the cleared areas. Lottia gigantea can then feed on the new algal growth. Lottia gigantea is unusual because of its large size and also because it has mantle folds on the lower surface of the mantle (pallial gills). It pumps water over gills by cilia, left to right. It has been estimated that large specimens may be 10-15 years. old. The rough limpet, Colisella scabra may be found living on the shell of Lottia gigantea.
Predator(s): Lottia gigantea is commonly eaten by the seastar, Asterias rubens, oystercatchers, Haematopus sp.and occasionally by people.
Prey: Lottia gigantea feeds on algae.

Feeding behavior
Feeding behavior(s): Herbivore
Feeding behavior notes: Like most snails, Lottia gigantea devotes considerable energy producing mucus that allows them to adhere to rocks as they move about. The mucus produced by Lottia gigantea nourishes microalgae. Therefore, when this limpet retraces its wanderings, it can graze on the algae that have been stimulated by its mucus trail.