Black Tegula (Tegula funebralis)

Description: The black tegula is a beautiful snail with a dark purple-black shell. Because they make the rocky intertidal zone their home, the black tegula’s shell gets battered by waves and surrounding objects over time, which leads to the tips of its shell getting worn down to the lower pearly-white layer. The shape of the shell is a dome-shaped, round spiraling cone that has four spirals, or “whorls.” These shells tend to reach about 3 cm in length. The snail inside the shell has a black foot and black antennae. The foot of a snail is the flat, squishy part underneath the shell that it uses to cling onto surfaces.

Habitat: Along the Pacific Coast of North America, black tegulas are found as far north as British Columbia and as far south as Mexico. Black tegulas can be found in the tide pools at Haystack Rock living on boulders.

Diet: Black tegulas are grazers that eat soft species of algae found underwater. To eat, these snails use their radula which has many rows of little teeth. The radula is often compared to a tongue - similar to a cat’s tongue - that is used to scrape algae off of rocks and other surfaces.

Tide Pool Tidbits:

• Male and female black tegulas can be identified by their foot color: males tend to have a paler foot than females do. The foot of a tegula can sometimes be seen sticking out from underneath the shell when they’re underwater.

• It’s pretty common to find black tegulas that have barnacles and mollusks, such as tiny black limpets or slipper snails, living on their shells. While barnacles and slipper snails stay in one spot, the black limpets will move around and graze on the algae growing on the black tegula’s shell. 

• They often travel at speeds of 0.6-0.8 mm per second but can almost double that speed if their predators, ochre sea stars, are sensed nearby.

Reference: Walla Walla University, The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept