Adventurous stories are told about the giant clam – it’s even said to have eaten divers.

The wrongly convicted giant clam

Everyone has heard the adventurous myths of giant clams snatching divers and keeping them in their watery depths. In German, the giant clam is even sometimes called the murderer clam (Mördermuschel). In reality, however, this mollusk closes its shell very slowly and presents no danger to divers.

In fact, man himself is a much greater threat to the giant clam: It is threatened with extinction thanks to pollution, climate change and overfishing. In Asia, for example, the sphincter of the clam is considered an aphrodisiac delicacy. This has led to giant clams being included on the Washington Convention (Convention on International Trade in Endangered Species) list, and is therefore prohibited from being killed and traded.

The giant clam (Tridacna gigas) is the largest of all mollusk species and can grow to 1.3 meters long and weigh up to 350 kilograms. They live in bright coral reefs in the Indo-Pacific, where they enjoy a symbiotic relationship with millions of microalgae. These microalgae are embedded in its shell lip and provide the clam with carbohydrates and oxygen. In return, the clam provides the algae with its metabolites for further utilization.

Visitors can admire the shell of a 90-centimeter long, 120-kilogram giant clam in the OZEANEUM’s 1:1 Giants of the Seas exhibit. The scale mounted in front of the display case provides the answer to the question, “Are you and your family as heavy as our clam?”