Answering Common Seashell Questions

Answering common questions about seashells.

While I write often about the seashells and sea snails I encounter on my travels, I sometimes forget what people really want to know about seashells. On this page I will answer some common seashell questions. I’m not a scientist, so my answers are simple and come from my own observations and research.

  • How do I identify my seashell?

To identify a seashell you’ve found, first you must know if it’s a gastropod or bivalve. This greatly narrows down options. Does your shell come as one piece or two? Spiral shells are gastropods (one-piece) and clams and scallops, as an example, are bivalves. Bivalves were created as two halves even though we most often find only one of the halves.

A shell that can be tricky is the slipper snail shell. For a long time I assumed it was a bivalve, but it is a gastropod because it is made in one piece.

The Slipper Snail is a Gastropod

Next, search for shells that are found locally wherever you found your shell. Even if it’s an uncommon shell, chances are that someone before you has collected the same type of shell. Search blogs, forums, and books that mention shells found in that area of the world. The Bailey-Matthews National Shell Museum is a good place to search.

Also, know seashell lingo. Along with the size, a shell is often described by mentioning the aperture (opening), body, whorls, lip, tooth, columella, hinge, etc. Color is important too, but sometimes the same types of shells can vary widely in color. Here is an excellent page, and site, to direct Florida shell collectors to identifying their shells.

  • What lives inside a shell?

Snails live inside shells. They create the shell as they grow. There are land snails and sea snails. Mollusks are snails of the sea and they make hard coverings (the shell) to conceal their soft bodies. However, once the mollusk dies and leaves an empty shell behind, other creatures can move in. Namely, hermit crabs. Where I live, I find lots of hermit crabs living inside shells.

Other living things can attach themselves to shells also and they don’t really care who is living inside the shell. See the barnacles on the shells below.

  • Are starfish (sea stars) and sand dollars considered to be seashells?

No, sea stars and sand dollars are echinoderms. There is no snail living inside them and they are completely different from snails that build shells. People do tend to call them “shells” mainly because they are found on the beach.

I rarely see sand dollars or sea stars, but I was lucky enough to come across this very tiny sea star on one of our boating trips.

  • How are seashells made? Where do seashells come from?

The snail creates the shell from what it eats and minerals it takes in during it’s life. The snail secretes a substance to build the shell around it and expand upon it’s home as it grows. The shell color also comes from what it eats.

Baby snails hatch from casings left by the parent snail. They begin very small and usually thousands of babies inhabit the casings because it’s so tough to survive in their habitat. This is a good place to mention that you should never collect a living seashell, or shells that have anything living inside or attached to the outside of the shell.

Egg Cases From Two Types of Sea Snail

On the left, the shark’s eye snail made this round, rubber ring that holds babies waiting to hatch. The egg case on the right belongs to some sort of whelk, but I’m not sure which. I’m holding a little Cerith shell next to it for size comparison.

My Interest in Seashells

I don’t know what it would be like to live far from an ocean. I grew up in Massachusetts, but even then I visited Wells Beach in Maine in summer, or went to Hampton Beach in New Hampshire with friends.

I wasn’t paying much attention to seashells back then. Being young, I was focused on more important things. Then, I lived in Florida for most of my adult life. The east coast beaches were only about thirty minutes away and we took the kids to the beach often. Now, the beach is even closer to my house. The point is that an ocean beach has always been within driving distance in my life.

Now that I am older, I prefer to scour the sand for interesting wildlife, plants, and shells that have washed up. At this point, it’s my favorite part of Florida. The crowds of people that have infiltrated this state have made enjoying natural Florida nearly impossible. So, we get on our boat and go off into the rarely visited waterways that snake through the Mosquito Lagoon estuary. My son fishes, and I walk the low-tide sand bars and mangrove island beaches.

Whenever I find something unusual I get photos and add them to my blog. I write about what I see, and the research I do is to inform myself and others. I hope that this will enlighten readers to the amazing world of sea snails and the shells they create. Knowing is appreciating.

I’m very lucky to be able to get out and view this nature for myself. All photography on this page is my own, as is most of the photography on this site. I use some of my photos for the design work I do and sell postcards, paper, puzzles and other products in my online store Seashells by Millhill.

I don’t have a problem with people collecting empty shells, but I am against buying shells from shops. It’s a money-making venture, which causes the death of living sea snails.

Do you have a seashell question? Leave it in the comments and I’ll try to answer it.

Read My Recent Blog Posts

Horse Conch Called “Knobless Wonder”

When a reader left me a comment about my big horse conch photo, saying that it looked unusual, I began to look more closely at the horse conch photos I had taken and compare them with photos online. Apparently the horse conchs I usually find are called “knobless wonder”. This is because they lack the large bumps many horse conchs have.

Many horse conchs are very knobby, as in the photo below, which come from Wikimedia Commons. In this vintage photo it’s clear to see the bumps at the top of the shell.

Chad Wade Brome holding a horse conch shell- Sanibel Island, Florida (3251676272)

Photo credit: Creative Commons attribution photo at Flickr and State Library and Archives of Florida.

Photographed Big Shells: Horse Conchs Found on The Muddy Flats

Check out this horse conch photo from the Bailey Matthews Museum showing how knobby a horse conch usually looks and compare the image to my photos below. At the museum they go on to mention the “knobless wonder” on that same page which “lacks nodules” and can be found in southwest Florida. Well, I don’t live in southwest Florida. I live on the central East coast. I don’t think I’ve ever found a large horse conch shell with big knobs.

The horse conchs above were photographed and put back into the water where they were found. The one on the left has a snail inside and lots of barnacles and such on the outside. The second photo was one of the first horse conchs I found while boating. It had living creatures attached to the outside of the shell and was encrusted inside with all kinds of things, but the snail was gone. I got some photos and left it there. Neither shell seemed to have the obvious “knobs”.

I don’t usually get to collect horse conch shells, and only have two, and they are big. They measure 10 and 16 inches in length (in photos down the page). It was just lucky that I have those because most big horse conchs we come across while boating are alive. I love to see the living snail. Sometimes they are buried in the mud awaiting the incoming tide, like in the photo on the right below.

Juvenile Horse Conchs

The small horse conch juveniles usually house hermit crabs. By the way, most small horse conchs I see out on the mud flats do seem to have the knobs. Maybe they are more pronounced when the snail is young, or maybe they are in fact the knobby kind. I will have to pay closer attention.

Horse Conch Comparison – Dirty / Clean (Somewhat)

The brown or black coating (called periostracum) that encrusts the shells is difficult to remove. It’s best to let it dry up and flake off on it’s own, which takes time. This is what I did for the two shells here. Below are comparison images from when the shell was found to now. In both instances it’s been a couple of years since they were collected and some coating remains.

big horse conch seashellhuge white knobless horse conch

The ten inch horse conch shell below has some bumps farther up the spire, but they are not as pronounced as some horse conchs. I cleaned this shell the best I could and eventually the coating peeled off, but not all.

florida horse conchhorse conch shell

How the Horse Conch Snail Moves

The huge, orange snail, which would have lived inside this shell, would be moving forward using the smaller end of the shell. When I look at a shell, I think of the pointed spire at the “front”, but that is really the back as he moves. This video is a good one for many reasons, but you can see a big horse conch moving as it chases down a tulip shell for it’s lunch.

The snail’s foot is used to maneuver. The shell I have is quite heavy, weighing in at 3lbs. 2oz. which is pretty amazing when you consider it’s carried by a snail! But the horse conch is no ordinary snail, and they do have the buoyancy from being underwater. For more horse conch information, watch this short video by the Whitney Laboratory at the University of Florida.

I love the beautiful texture of the shells. This largest shell has become quite white, but it also has some mold from sitting outside in my Florida garden. I’ll attempt to clean it up and get more photos. The periostracum is still flaking off.

In the video link above, I learned that horse conchs can live to be 30 years old. This shell is about 16 inches long and the maximum is about 24 inches. I think this conch had a pretty long life in order to create a shell this size. Read the story about how I came to be the caretaker of this shell.

Keep Reading: Recent Posts

Second Stop on Our January Boating Trip – Three Sisters

Once we finished up at our first stop (read that post here), we boated up to Three Sisters which is a small group of mangrove islands in the backwater area of the Indian River. The tide was going out, which is my favorite time to beach-comb. We parked in behind the island and I searched for something to photograph.

Once again, as on the first stop of our boating trip, there were no larger shells and no hermit crabs. The tide was low and going out and the water was clear. Without a closer look, this area seemed to contain mud only and a few birds.

  • Three sisters island
  • Clear water in January along the Indian River
  • Bird tracks in the mud
  • Mud tracks
  • Weird hole in the sand

I thought the bird tracks were cool, and the other tracks may have been some kind of crab, but I’m not sure. There were holes in the sand so I suspect that crabs had dug them. I find this low tide landscape interesting, but much more so in the warmer months when living things are everywhere!

What I found was loads of very small sea snails. After finding the sand collar on my first stop, and now loads of “baby” sea snails, I’ve concluded that this is the time of year for babies to hatch. However, I have no idea where all the hermit crabs and larger snails have gone.

One of the little tide pools was teaming with life. All the tiny snails were mostly covered in mud and slowly wandering around. I carefully scooped one into a clam shell I found to take the video above. They looked like little clumps of mud. I cleaned the mud off to get the photo showing the actual tiny shell.

Lots of tiny shells
One of many tiny shells / snails I found

Babies or Simply Tiny Sea Snails?

As you can see, the tiny snail below looks different from the one above. Juvenile sea snails are hard for me to identify. All I can go by is what type of gastropods I usually find in this area – horse conchs (according to others it is bright orange as a baby), crown conchs, lightning whelks (opening on the left) and pear whelks. To a much lesser extent I see knobbed whelks, tulip shells, and have a few broken channeled whelks – usually shells only.

Because of the wide dark and light stripes on the shell below, I would guess it’s a baby crown conch. The shell above, no clue. Maybe it’s just a small snail and not a juvenile, but because there were so many tiny shells all together I was thinking that they “hatched” recently. I found no type of egg casing, but that could easily have washed away with the tide. I’m pretty much admitting that I just don’t know!

Tiny sea snail with striped shell
Tiny striped sea snail – could this juvenile be a crown conch?
crown conch
Stripes and spikes of the crown conch shell

I did find one buried Southern quahog clam shell. I carefully dug at it to see if it was alive, but only one part of the clam was there, so I took it home.

Buried seashell
Pretty buried bivalve shell
Clam shell dug out of the mud
Southern quahog clam shell
Stout tagelus bivalve shell
Tagelus shell

All this photo sharing and research on juvenile snails has my brain hurting, so I am signing off for now. What I do know is that these backwater areas look very different (shell-wise) during the winter season.

If you haven’t read the first part of this story, check it out here.

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