Head to head
Slipper Limpet vs Common Limpet
Slipper Limpet
VS Common Limpet
The slipper limpet and the common limpet look alike at a glance, with low, cone-like shells, but one is a native grazer of rocky shores and the other is an invader of sheltered bays.
| Slipper Limpet | Common Limpet | |
|---|---|---|
| Scientific name | Crepidula fornicata | Patella vulgata |
| Group | A sea snail with a limpet-like shell, not a true limpet | A true limpet, with a low, cone-shaped shell |
| Shell | A shell with a small internal shelf like the seat of a slipper | A low, cone-shaped shell, usually around 5 or 6 cm across, with faint ridges from the top to the edge |
| Diet | Filter feeder, drawing in plankton and tiny particles with water flowing through its gills | Herbivore, grazing on the thin film of algae on wet rock, scraped up with a rasping tongue |
| Lifestyle | Settles in stacks of several animals, up to a dozen or more | Clamps itself to rock with a muscular foot and suction, and returns to a home scar after grazing |
| Sex | The animals at the bottom of a stack are female, those at the top are male, and a male can change into a female | Typically male when young and changes to female as it grows older and larger |
| Origin | Native to the east coast of North America, brought to Europe in the late 1800s, probably with imported oysters | Native to rocky shores of the north-eastern Atlantic, from Norway and Iceland south to Portugal |
| Conservation status | Not Evaluated, and invasive in sheltered coastal waters of north-western Europe | Not Evaluated, and a common grazer of rocky shores |
Slipper Limpet vs Common Limpet: common questions
Is a slipper limpet a true limpet?
No, it is a sea snail whose shell looks like a limpet, with a small internal shelf like the seat of a slipper.
Why is the slipper limpet a problem?
It forms dense beds on oyster, mussel, and other shellfish beds, where it competes for food and space and smothers the seabed with mud.
Do both change sex?
Yes, both start as males and change to females, the common limpet as it grows older and the slipper limpet as its position in the stack changes.