Healthy Habits,  Science

Where do Sea Shells come from

Where do shells come from, and how are they made? Sea shells are as interesting to adults as they are to children. Fascinating to both in their beauty and mystery.

We almost annually visit Stilbaai. This is a small-town in the Western Cape, South-Africa.

Stilbaai is a small coastal town – they have a website with all their activities and information if you click HERE . My Husbands Parents live here full time now, and is truly is a privilege to be able to come here and spend a whole month on holiday. The first 2 weeks before Christmas is usually crazy with all the matrix that come here for matrix vac, but it gives a good vibe, the beaches are packed and the local pubs and restaurants try to keep up at their best. Most people that come here are literally regulars –it’s amazing to see everyone again and again every year – it’s like going on holiday alone but also with friends!

It’s a very popular holiday destination for young people and also young families. Throughout the year it is basically a haven for the retired community and for 30 days of the year in December they are unfortunately invaded by us, the regular inland dwellers that want to experience the amazing place they call home.

One of my favourite activities here is to visit the Skulpiesbaai Nature Reserve. Here you can find the ancient fish traps. According to history, these traps have been built by the Khoisan people more than 3 000 years ago and are visible at low tide. The fish traps have National Monument status. When visited at the right time of day and right time of the tide, you would be able to snorkel in these fish traps and see the beautiful fish that are temporarily trapped until the high tide comes to set them free again. These traps also collect beautiful seashells.

All along the beach the shells are washed up in their millions. I’m not entirely sure why they are present here more than on the main beach but it makes for wonderful adventure to come here really early in the morning and look at all the beautiful shells.

Some big, some small, some bright and some dull. Here are some below

Here are some Shells From Stilbaai:

Here are some Shells From Snt. Frances Bay in the Eastern Cape:

Here are some Shells From Durban in KZN:

The quality isn’t good, the picture is very old.

Here are some Shells From Tanzania:

I visited a few websites and their references are all below for further reading.

Throughout history shells have been not only important geological component for the environment but also important in human culture. Shells have been used as religious trinkets, as money in place of silver and gold. And most commonly as food. Today seashells form part of a multi-billion dollar portion of the global commercial fishing industry.

For the larger portion of shells we come into contact with are produced by Mollusks. These are sails like creatures. Mollusks are small invertebrate creatures that have slimy – soft vulnerable bodies. Their shells protect their fragile bodies from the elements and predators that hunt them. They are situated in the sea for most of their lives and takes in salts and chemicals that are in the sea. They are categorized into different family groups same as insects. Over 110,000 estimated species makes it one of the largest phyla of animals.

One website summed up all the different categories very well – Read more about these species here –Click here!

There are six major classes of Mollusks that have shells:


Shells are excreted from the outer surface of the creature that is referred to as the mantle and are made up of calcium carbonate. The creature grows and gets bigger, the shell gets larger and more calcium carbonate is exuded from the mantle. Even though the shell is attached to it, the shell does not form part of the mollusks living body, and is not made from mollusks cells.

The Colours and patterns are specific to different species. Most of the time the differences in the species are visible even if they are still similar on the first glance. As always in nature the creature may die due predators, illness, or even age but in the end, the durable shell remains. Ocean Tides and currents carry shells underwater where they often wash up onto the beach. Different diets and different environmental conditions contribute to all the different appearances of the shells.

Warmer waters contribute to brighter and more colourful shells whereas colder waters make for more solid colours and less colourful shells. In warmer environments like the tropics the predators are fiercer like with insects the mollusks tend to then have brighter colours and patterns to ward off predators. Others have developed a more streamline shape as to get away from predators faster. The shells also helping different situations to either anchor the mollusks or to prevent them from sinking into sand.

Hermit crabs also inhabit shells, 1000 species of hermit crab exist today. They also rely on these shells to protect them from predators. Hermit crabs on the contrary do not kill or evict the mollasks from their shells. They wait patiently for the shells of dead mollasks. They also do not clean out the shells and rather wait for other predators to do the job.

According to Helen Scales, Marine biologist – The oldest known hermit crab fossil was discovered in 2002, in the Yorkshire, England village of Steepton. Paleontologist Rene Fraaije spotted the crab in the shell, which, Scales writes, belongs to an ammonite, “an extinct cephalopod that swam through far more ancient seas, in the Lower Cretaceous around 130 million years ago. After it died it sank down to the seabed where a crab scuttled past, picked it up and climbed inside.”

That’s pretty amazing, I love staring at the water, sitting very still, and then suddenly all the shells start walking, and you quickly realise that all the shells are living. Inhabited by hermit crabs. I have twice collected shells that I had to quickly return to the ocean after realising that I accidentally collected a shell that was still a home to a little creature. Now I’m very careful.

When we visited Tanzania we took a boat to Zanzibar – we walked through the streets of stone town a popular market in Zanzibar. There were shells for sale. HUGE ones, the size of my head. Somehow buying them felt wrong.

When buying shells the chances are that those creatures were collected and killed for their shells. It’s sad to think that something so magical and beautiful had to live and work so hard and long on such a beautiful shell to be evicted for our pleasure. The shell trade is estimated to target about 5000 species of mollusks each year. Research has shown that shells had decreased in size and that larger species are very rare and numbers are almost depleted.

Here are the Shells From Zanzibar that I saw next too the road:

Something interesting is that it is illegal in some countries to remove these shells from their natural habitat, and that even if you were to buy these shells it would be a great disappointment when you get to customs as the shells would unfortunately be confiscated.

I did collect some beautiful shells in Zanzibar, when we got to the airport there was a huge sign saying that all shells will be prohibited to leave. I got such a fright, knowing that I very well had my bag stuffed with shells. I went through the scanner and rushed to see what they spot in my bag. I was terrified. I didn’t want to get into trouble for something that I innocently wanted to take home as a memoir…

On the scanner is was amazing to see what they spotted – the machine automatically spotted all my shells….Blood rushed to my face! The officials talked to each other and then let me go through. Apparently they need to be a certain size and species to let a few red flags go up. I was so relieved.

I’m now more careful when collecting shells, I am still in love with them but I have found that they are more beautiful on the beach than in my house. I think that it is important for children to be able to collect shells and fall in love with their beauty, be curious and ask questions. But it is our responsibility as adults to teach them the conservation and respect for nature and it’s creatures.

Enjoy the Holidays and the pretty Shells if you see any!

XOXOX – Jani

Reference list:


  • sande

    I really enjoyed your blog “where do sea shells come from”. I love going to the beach. I once lived near the beach and i loved it. It was the northwest beaches of Washington. I now live about 3hr from the ocean beaches. Over the years i have collected shells, agates, petrified and drift wood. Friends have given me shells (and beach sand) from places they’ve gone. I seldom get to the beach now due to changed circumstances. Once again thank you for your blog.

  • DeAnna

    Excellent article. I’ve always wondered where shells came from. I make and sell jewelry and I was looking for some shells to use in my craft. Do you have any idea where I could buy cruelty free shells. If they arent cruelty free I refuse to use them.

    • Jani du Toit

      Hi DeAnna

      Thank you for your comment! Glad you liked the article!
      I’m not sure where you can buy shells – I usually just collect from beaches. Maybe google to see if someone in your area sells shells.


  • Sharon


    I have found that there are shells of all sizes in craft stores. Whether they are real or not I am not sure but they certainly do look real. Good luck in finding them.


  • Smita Upadhye

    I really enjoyed reading your article “where do sea shells come from”. Superb, Very informative article indeed. I also collect all sorts of shells. I create artifacts by using them and draw n paint them. I had big shells, corals with different colours & designs at my home town. When I migrated to NZ my shells collection increased by adding the most beautiful New Zealand Paua shells to it. I had never seen before such a pretty shell like it.

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