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

March Hermits in Medium Size Horse Conch

A chilly boat ride took us to Three Sisters, among other places, where we found interesting shells filled with hermit crabs. Often I have seen tiny horse conchs, and a few times we’ve seen massive horse conchs, but this horse conch was medium size.

Hermit crab in a medium size horse conch shell
Spotted a cool horse conch among the oyster shells

As I waded through the 62 degree water on a 60 degree day, with a wind chill, I came across this pretty little shell. I knew right off that it was a horse conch, but it was larger than the ones I usually find.

Smaller horse conch seashell found in the mud
Dirty but pretty seashell

This shell had a very large hermit crab inside and he was tucked way down in. I couldn’t keep the shell so I got a few pictures on my iPhone, which I hoped would come out.

Here you can see the pretty lines and bumps which make up the shell, and orange to reddish brown coloring. I’m guessing that this shell was about 5-6 inches long. The snail had died for whatever reason, and a large hermit crab had moved in. Although I previously had read that Hermit crabs do NOT kill mollusks for their shell, this article has opened my eyes to the possibility. However, the crab mentioned lives in farther southern waters.

It is curious as to how hermit crabs just happen to find empty shells the correct size to hold their bodies. In this vast expanse of river, how would that happen? Hermit crabs don’t run around without shells, so how does it all begin?

A few weeks ago when we were out on the river, there were no hermit crabs anywhere, and very few shells at all. It makes me wonder if any of the hermits I see will kill a mollusk / snail and take over the shell for their home.

horse conch
Smaller horse conch shell with hermit crab inside

The horse conch shell was not in perfect condition and it was encrusted with mud, but it was a beauty just the same. Had it lived, it may have become up to 2 feet long. We have occasionally seen living horse conchs out on the little islands along the Indian River backwaters.

horse conch

We drove the Hewe’s Redfisher in behind Three Sisters and walked the sandy areas that were showing at low tide. But the water was coming back in, so the sand was disappearing. My son found a starfish / sea star, which I have never come across ever. This one was unfortunately dead and was missing two legs with another one broken. I came across a few gatherings of hermit crabs where it appeared they were checking out each other’s shells. We saw lots of little “baby” mollusks crawling about as well. This area is usually full of interesting wild creatures from the sea, and today did not disappoint.

Medium size horse conch seashell
Pretty horse conch

Various Horse Conchs I’ve Seen on Florida’s East Coast

  • Me and my daughter with horse conch
  • horse conch seashells
  • living horse conch
  • Crusty horse conch living on flats
  • juvenile horse conch seashell
  • horse conch seashell
  • old horse conch seashell underwater
  • Four hermit crabs in the wild

Even if the shells can’t be collected, the photos are fun to share. Being educated about what can be found in this wilderness area of Florida is my goal with this blog.

Souvenir Horse Conch Seashell

After the mollusk died, this large seashell was left to be buried under the sand, until a friend stepped on it and dug it up.

A friend of my sons has been visiting from New Hampshire and wanted to go fishing. While the boys were out on the boat, they jumped into the water to cool off and the friend felt something hard under the sand. He said he felt a rock, but my son quickly corrected him saying there are no “rocks” in Florida (except coquina rock). So The Friend began digging. What he pulled up was a huge, empty horse conch shell.  What a vacation souvenir….!!!!!!

big horse conch seashell

This is the biggest shell I’ve seen. It was buried deep in the sand which tells me the mollusk died and then the shell was buried in sand as the tide moved. No hermit crab is large enough to live in a shell this size, and if the mollusk still inhabited it, it would be very apparent (See my page about the Florida Horse Conch). It was an empty horse conch shell.

big horse conch seashell
Skittle the Cat checks out this big seashell

I sprayed it off with the hose and left it outside to dry. I will chip away the barnacles and other stuff, but getting the black periostracum (dark coating which covers the shell) off is difficult. The shell underneath may be very pretty, or not. One thing I know is that this is an amazing gift from the sea, created by an amazing animal.

The Friend is not interested in taking it home with him, so I will attempt to clean it up and put it in my garden.

huge horse conch seashell
The big horse conch is 17 inches long!

One time when we were out on the boat exploring the islands I had found a horse conch empty on the sand and it now sits on my kitchen windowsill (the brownish one in the photo above).  That shell is small compared to this beast!

And here’s a photo with Skittle the cat.  She insisted.

horse conch seashells
Two shells and one black cat

UPDATE: I did not do any cleaning to this shell, except to brush off the barnacles and growths, which is easy when they dry up.  As it sat out in the sun in my garden, the black stuff began flaking off on it’s own.

Underneath, the shell is white. I’m guessing that once the snail died, the empty shell was bleached by the sun. With the tides moving sand around, eventually it became buried, which is where it stayed until our friend stumbled upon it.

big seashell in the garden

Finding the Shell Beneath the Black Coating

This shell is so large that the only place for it was in my front garden. After time, it’s become moldy simply from the Florida humidity. A lot of the periostracum coating has flaked off, so I decided to try to clean it up a bit more. I have scrubbed it with a brush using ammonia and water. Then it was left out in the sun to hopefully remove the green and black mold.

So no great coloring, but still an awesome seashell.  In case you are interested in the rules and regulations about collecting seashells in Florida, read my post about the rules on collecting seashells in Florida.