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Five Facts about Giant Clam

Marine Life medium12th edition of Marine Life monthly post. I can’t believe that it’s been a year this monthly post existed. Thank you for keep following this monthly post! This monthly post aims to share information on specific marine life species and to promote their conservation.

Here is our video how a giant clam closes its shell. Dutchie took this movie in Raja Ampat, Indonesia.

I always find the giant clam as a pretty animal because of its beautiful color patterns on its mantles. I was inspired to write about the clam after watching a sad short movie of a dying clam sucking salt on the kitchen table to stay alive. Little I knew about the clam when I watched that movie.  After reading some articles about the clams, I find five interesting facts about this animal that may surprise you. This time, I am focusing only on the giant clam (genus Tridacna)- the largest mollusks on earth.

1. Clam does not eat human or chew any part of human’s body

The giant clam is often being called as a man-eating clam and considered dangerous animal. There is a myth of the giant clam as man-eater animal in South Pacific area. The fact is the giant clam does not eat human who was swimming near to it or accidentally steps on it. I am sorry to disappoint you, the giant clam feeding sounds boring but certainly good news for human: its feeding mainly by filtering the nutrients from the water.

The giant clam closes its shells in action of defending itself. Based on our experience of seeing the giant clams closed their shells, they were unable to close their shells completely.

Giant Clamp

Giant Clamp

2.  It lives up to 100 years 

Yes, the giant clam can live that long and even longer! The clam usually stays in one place for the rest of its life. It is a bottom-dwelling animal, it stays on the ground and growing bigger. The size of the giant clam could reach 1.3 meters and weight to 250 kilograms.

3. It is a hermaphrodite 

A giant clam has both male and female reproductive organs, it can produce offspring without another clam as a partner. At first, it reaches its maturity as a male,  after a year, it becomes a hermaphrodite.

4. It can produce “pearls”

Have you heard Pearl of Allah or later being named as Pearl of Lao Tzu? The pearl was declared as the largest pearl ever found in the world and it produced by a giant clam in Palawan, the Philippines, in 1934. More story about this special clam’s pearl, please read The Pearl of Allah: the Facts, the Fiction, and the Fraud. Pearls produced by the clams usually very rare but the clams have the capability to produce the ‘pearls’ that categorized as “Calcareous Concretion”. Unlike the oysters’ pearls, the clams’ pearls usually not valuable due to its quality and irregular shapes.

5. Vulnerable

Unfortunately, some species of the giant clams (genus Tridacna) are listed by IUCN Red List as vulnerable species and its population close to being endangered. This happened because of excessive fishing exploitation. The giant clam’s adductor muscle is popular because it believed to have aphrodisiac powers. Its colorful mantles also popular for interior decoration. The giant clams farming is now developing in Micronesian countries. I am not sure how sustainable the nursery in practice but perhaps that could stop the reducing number of the wildlife giant clams.


  1. It is always so exciting to read your facts about life below the water then comes the latest on the endangered list which is always so sad to read. So hope these magnificent clams get to live in peace, undisturbed!

  2. I love this, as a kid and watching old movies – the idea of a giant clam always scared me, especially when it was time to go in the ocean. Love the phots ~ such a strange world below the water compared to ours…more beautiful too!

  3. Is that YOUR hand in the movie…you got guts. Alligator, clam…same thing. I bet their pearls are big. Hey, btw, I couldn’t open your most recent post…sign says it’s not there? Is it Bali wi-fi, or your site?

    • 😀 Alligator is animal that I am afraid of! 😀 😀 so maybe I will stay away for diving with them 🙂 Oh I deleted that post – it was a reblog from my old post. Something wrong with my WP Reader that I can not see some bloggers post properly, so I need to follow my own blog and see if that happens to my post as well..but now the WP reader works again so I can catch up 😀 😀

  4. Indah, thank you so much for these thoughts. I used to live in the Andaman and Nicobar islands a long time ago and I remember these. And yes, even there they were known as killer clams for the closing of their shells on some swimmer’s foot etc. I don’t know how far that is true, but I used to hear tales about them. Also, that is how they used to pry them away too – stick a crowbar in them and the shell would close up and then they would pry them lose from their coral homes, even so far as to just suspend them over an open fire to cook them, shell and all. Sad, really. I am grateful to you for bringing this to the notice of the world. Thank you.

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