Giant clam
Tridacna sp.
- Not on exhibit
- Animal type
- Invertebrates
- Ecosystem
- Coral reefs
- Relatives
- Other clams and mussels, scallops, oysters; Phylum: Mollusca; Class: Bivalvia
- Diet
- Sugars and proteins produced by the algae living in its tissues; tiny, drifting plants and animals filtered from the water
- Range
- Western Pacific coral reefs, Indian Ocean and the Red Sea
- Size
- The largest species, Tridacna gigas, can grow to 4.25 feet (1.3 m) long and 550 pounds (250 kg)
Meet the giant clam
Like corals, the giant clam lives in partnership with tiny plantlike algae (called zooxanthellae) that reside inside the clams’ tissues. And as with corals, the arrangement helps both creatures. The algae gain protection from grazing animals; the clam grows large with the benefit of food produced by the algae.
Natural history
At home on reefs throughout the Indian Ocean, the South Pacific and parts of South Africa, the giant clam lives on shallow reef flats down to depths of around 66 feet (20 m). Below that, the algae they depend on to survive wouldn’t have enough sunlight to grow.
Conservation
The giant clam, Tridacna gigas, is rarely found among coral reefs these days due to years of overharvesting. However, giant clam aquaculture has become a successful alternative to wild collection. Giant clams are a highly regulated species, protected under the Endangered Species Act.
Cool facts
- As its name implies, the giant clam is the world’s largest living marine bivalve (clam, mussel or oyster).
- Their soft bodies account for only about 10 percent of their total weight.
- Once a giant clam settles into a place and begins to grow, it stays permanently attached to that spot for life. A giant clam can live 100 years or more!
- The clam’s bright colors are the result of the algae living inside its body.
- The giant clam has falsely been called a “human killer”; no human death has ever been attributed to this animal.
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