Seashells by MillhillAbout the Shark’s Eye Seashell

One of my favorite seashells to come across is the Shark’s Eye. The slightly flattened, round shape makes it unmistakable, but often the shells I find are covered in mud and guck. Below is a Shark’s Eye crusted over with hard mud.

mud covered round sharks eye seashell — Yes, it’s a seashell!

The Shark’s Eye has the scientific name “Neverita duplicata” and is the family Naticidae. Baby’s ear shells, see photo below, and Moonsnails are related to the Shark’s Eye.

Baby's ear seashell — Baby’s ear seashell

The spire is tightly swirled in the center and can be blueish in color – hence the name. The rest of the shell is usually brownish with some maroon and gray, and has a dark interior. It is very smooth.

Beautiful shark's eye seashell — Shark’s Eye

On a recent boating trip to Three Sisters, I came across two very pretty Shark’s Eye shells. They were in shallow, clear water. These are the pictures I took of the two different shells. Both were about 2 inches in size.

Shark's eye seashell bottom — Sharks eye opening

Both beautiful shells contained hermit crabs, of course! You may be able to just see the legs tucked down inside the shell in my photo below. The crabs usually hide when the shell is held or moved.

hermit crab inside sharks eye shell — Hermit crab hiding inside

What’s Inside a Shark’s Eye Seashell?

Most often I see Striped Hermit crabs inside shells, but only when the original snail has died and left the shell empty.

One day I was at the ocean beach, in New Smyrna, and I found a little shark’s eye shell with the snail inside!

I was sitting at the edge of the ocean enjoying the warm water of a tide pool, and there he / she was. I picked up the shell thinking I had found a keeper, and discovered it was alive! I tucked him back into the sand, after I took a photo. He was small enough to be ignored by passersby, and mostly buried. He was probably waiting for the tide to come back in.

shell in the sand — Very small living Shark’s Eye on the beach

Pam, at “I love Shelling” has a video of a living shark’s eye moving along her hand. She lives on Sanibel Island, the Gulf coast, and you can see that video here.

Even Broken Shells Are Pretty

Nearly every Shark’s Eye shell I find contains a hermit crab – unless the shell is so broken no hermit could live in it. That is why my collection only contains bits and pieces of the Shark’s Eye shell. I sometimes find broken shells at Ponce Inlet, where many shells are black in color.

smooth parts of different sharks eye shells — Pieces of Shark’s Eye seashells

Shark’s Eye Habitat and Fun Facts

This snail lives in sand where they hunt for clams to eat. According to my reference book, they are found all around the Florida coast. Of course they are easier to find in some places than others.

Once they find dinner, they bore holes into the shell of their victim and inject the clam with enzymes to kill it. Then, they suck out the remains. If you find a shell with a hole in it, now you know how the mollusk died. Other predatory snails eat this way as well.

Often shells with tiny holes lost their mollusk to a predator who drilled that hole to eat the contents!

Some people call shark’s eye shells “shark eye” or use “moon snail” to describe all these similar shells. All I know is that they are not all exactly alike and each has a different scientific name. The Shark’s eye is the largest and can be 3 inches across. The Gulf Coast area has shells like this, but with an “eye” area that pops out more from the shell – see “Neverita delessertiana“.

My shells have been found on the Atlantic, east coast of Florida and mostly out on the island beaches in the backwater areas. The broken pieces wash in through the inlet, but there are not a lot of them. This type of Shark’s eye can be found all the way up into New England.

My large broken shell lets me get a look at the smooth interior parts. This is the body whorl where the mollusk that created the shell lived his life. It may have been home to a hermit crab before it was broken apart by waves and sand.

shiny inside body whorl of a Shark's Eye seashell — Inside a broken sharks eye shell

The Unusual Egg Case of a Shark’s Eye / Moon Snail

When I look up “sand collar” or “round egg casing” the Moon Snail is the mollusk mentioned. I usually refer to this shell as the Shark’s Eye. It is the same type of shell I regularly see in my area – brown with a center “eye”. So the egg casing below, which I found in the areas I beach-comb probably belongs to this shell. You may call it a Moon Snail where you live. The difference seems to be in the coloring.

I found the sand collar below in January 2021 and wasn’t sure what it was. I’ve never found one before. In fact, I found two near each other in a shallow backwater area of the Indian River.

The center opening of the collar gives an idea of the size of the “mom” who laid the casing. It feels like rubber, but is made of sand and baby moon snails. Once the babies hatch the collar will disintegrate.