Limpet Snail ~ A Marine (Saltwater) Mollusk ~ Patella sp.

Keyhole limpet (Diodora aspera) with coral leaf algae (Bossiella sp.) - Salt Creek Recreation Area, Clallam County, Washinton, USA
Keyhole limpet (Diodora aspera) with coral leaf algae (Bossiella sp.) - Salt Creek Recreation Area, Clallam County, Washinton, USA | Source
Giant Keyhole Limpet Underside
Giant Keyhole Limpet Underside | Source

One of the marine aquariums that I set up in my home was a 55 gallon live reef tank. This means that I used live rock (rock from the ocean that contained live organisms such as corals, snails, anemones, limpets, etc. already on it) to create a living reef. These “live rocks” contained many hitchhikers which then found their way into my saltwater aquarium. One of the hitchhikers that I discovered was the limpet.

Answers.com defines a limpet as: “Any of numerous marine gastropod mollusks, as of the families Acmaeidae and Patellidae, characteristically having a conical shell and adhering to rocks of tidal areas.”

The second definition was: “One that clings persistently.” This definitely describes the limpet, which can be found in both fresh and salt waters, and in warm and cool waters, all over the earth.

The third definition may be familiar to war and military buffs: “A type of explosive designed to cling to the hull of a ship and detonate on contact or signal.” Again, it was used to describe something that clings.

Marine Mollusk / Saltwater Snail

Limpet is the name given to a snail that has a shell that is conical in shape, but whose shell is not coiled or appears not to be coiled. Although limpets can be found in freshwaters or saltwaters, we will be discussing the saltwater or marine limpet. Limpets typically range in size from ¾” (2 cm) to 4” (10 cm). This conical shape enables the limpet to survive the thousands of wave crashes it experiences every day without losing its footing.

Owl Limpet -  It is sometimes called "Farmer John".
Owl Limpet - It is sometimes called "Farmer John". | Source

Notice the etch type marks on the rock around the limpet. These are caused by its feeding behavior, and are made by its ribbon-like tongue which consists of rows of teeth.



Slipper limpets (Crepidula porcellana)
Slipper limpets (Crepidula porcellana) | Source

Most limpets have gills, but a few have developed the ability to breathe air much the same way as we do, adapting part of their mantle cavity to function as a lung.

Like their relative, the nudibranch, the limpet has a very strong muscular foot that acts as a clamp. They are able to attach to the rocks and coral surfaces with such extreme forces that it is nearly impossible to remove them from the rock. In fact, it will allow itself to be totally destroyed rather than release its hold. This could literally be described as a “death grip”.

This clamp down action helps them survive in another way also. They clamp down to seal their shell edges against the rock surface, trapping some water inside their shells, literally sealing themselves safely inside. This is beneficial to protect them from exposure to the air and the sun when the tide goes out and they find themselves exposed to the open air.

Limpet (Patella sp) - photo taken at Barns Ness, Dunbar, East Lothian, Scotland.
Limpet (Patella sp) - photo taken at Barns Ness, Dunbar, East Lothian, Scotland. | Source

Patella sp. Limpet

The Patella limpet, which can grow as large as 8 inches (20 cm), is in serious danger of becoming extinct because of over-harvesting by shell collectors and dealers, and by others who use it as a food source.

An interesting note: in humans, the patella is the kneecap bone. It is obvious where these Patella Limpets got their name.



Chemicals from the Keyhole Limpet are being tested in the treatment of cancer.
Chemicals from the Keyhole Limpet are being tested in the treatment of cancer. | Source
Limpet shells come in a variety of colors. Click on the image to get a closer look.
Limpet shells come in a variety of colors. Click on the image to get a closer look. | Source
Hitchhikers - Other sea creatures hitch rides on limpets.
Hitchhikers - Other sea creatures hitch rides on limpets. | Source

Most limpets are herbivores, grazing on algae. Some smaller species of limpets, live on seagrasses and graze on the microscopic algae growing on the seagrassess. Their tongues are very similar to a cat’s. They use their tongues to rasp, or scrape, the algae from surfaces. If you have ever been licked by a cat, you would understand this process.

The limpet species, Lottia gigantean, actually tend their own garden patches. They establish a territory and aggressively push other creatures out of their area by ramming them with their shell. Therefore, insuring themselves of a constant food source. This territorial behavior is atypical.

Limpets find themselves as a food source to starfish, shore birds, fish, seals, and humans. To defend themselves from these predators, the limpet will clamp down on a surface in their environment. The second method they utilize is to flee. This is not as effective, because to a limpet, fleeing means moving at the speed of several inches an hour!

Limpets have been documented to live as long as 20 years.

Limpets spawn once a year, usually in the winter, by releasing eggs and sperm into the water column. Their larvae live free floating in the ocean waters for a couple weeks and then settle down to the ocean floor.

Limpets also exhibit homing characteristics, always returning to the same place after eating. Often times, they will use this same spot their whole life. Limpets, who do not have any eyes, leave mucus trails, like a land snail or slug, which enables them to find their way back home.

Limpets are related to abalone, nudibranchs, sea hares, octopus, squid, scallop, mussels, oysters, clams, chitons, and snails.

The Keyhole Limpet has developed a symbiotic relationship with a worm that lives under its shell. When a starfish attacks this limpet, the worm will come out and zap the starfish causing it to retreat. The limpet and the worm serves as protectors for each other.


All Rights Reserved

Copyright © 2011 Cindy Murdoch (homesteadbound)




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How to Gather and Cook Limpets

In the video below, Fraser Christian of CoastalSurvival.com, a coastal forager, shows how to gather and cook limpets.

Other Sealife Articles By This Author:

More by this Author


Comments: "Limpet Snail ~ A Marine (Saltwater) Mollusk ~ Patella sp." 17 comments

Movie Master profile image

Movie Master 5 years ago from United Kingdom

I had no idea that some Limpets come so big, and can live upto 20 years! There shells are truly lovely.

I really enjoyed reading, I've learnt a lot!

Many thanks for sharing.


Gypsy Willow profile image

Gypsy Willow 5 years ago from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand

Wonderful hub on these inoffensive sea creatures. I picked up some on Sydney beach in Australia and they look just the same as the shells I find in Wales.


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

Movie Master - It is amazing how complex and varied sea life really is. They really do have pretty shells, one of the reasons that some of them are endangered. Thanks for stopping by!

Gypsy Willow - How wonderful to have been able to pick them up at 2 wonderful locations. I don't get to the beach often, but I love to read about sealife and to watch the learning channel and the discovery channel. I'm glad you enjoyed the hub.


Cloverleaf profile image

Cloverleaf 5 years ago from Calgary, AB, Canada

Hi Homesteadbound, these creatures are really lovely. I especially like the keyhole limpet, very unusual. Wouldn't it be incredible if the chemicals in them could actually be tested positive in a treatment for cancer?

Cloverleaf.


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

cloverleaf- thanks for stopping by. And, yes, it would really be neat if this creature would hold the secret to the cure for cancer.


Eiddwen profile image

Eiddwen 5 years ago from Wales

A great hub ,so very interesting.

Take care

Eiddwen.


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

Eiddwen- I'm pleased that you enjoyed the hub. They really are interesting little creatures. Thanks for stopping by.


jami l. pereira 5 years ago

Awesome job! , i enjoyed the read , amazing the wonderful creatures of the sea..AND these are really cool too :) Too bad people destroy everything , have a great evening , i voted up all the way across the board , except funny :) thanks again for the read:)


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

jami l. pereira - I think the first picture looks like a woman's hat. These are interesting creatures. Thanks for stopping by. Have a great evening and week.


brennawelker profile image

brennawelker 5 years ago

Never thought of Limpet which can live for so many years.Amazing creatures. Very nice hub!


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

Brennawelker - it is amazing that they can live that long, isn't it! There are so many amazing creatures in the oceans.

Thanks for stopping by!


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

Brennawelker - it is amazing that they can live that long, isn't it! There are so many amazing creatures in the oceans.

Thanks for stopping by!


adrienne2 profile image

adrienne2 5 years ago from Atlanta

Well I feel like I just have a mini-course in Marine Biology. Very nice hub! Thank you for sharing, also I didn't know about the Keyhole Limpet being tested for the treatment of cancer. Your pictures are amazing.


Moon Daisy profile image

Moon Daisy 5 years ago from London

Another great hub! I have been fascinated by limpets ever since I used to find them at the beach as a child. It's great to learn some more facts about them after all this time.


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

adrienne2 - Wow... marine biology ... I'm glad you enjoyed it. Thanks for stopping by!


Ahydz profile image

Ahydz 5 years ago from Philippines

Interesting hub! Voted UP!


homesteadbound profile image

homesteadbound 5 years ago from Texas Author

Ahydz - Thanks for the votes and thanks for stopping by!

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