Giant Clam

giant clam Tridacna gigas, the largest bivalve in the world, found in tropical waters of the Indo-Pacific region. It can measure well over 1 m (the record is 1.4 m/4' 6") across, weigh several hundred kg (more than 500 lb), and is reputedly capable of living for centuries. Half-shells of this huge creature have been imported to Europe to serve as decorations, fountains, or washbasins.

T. gigas has a small relation, T. maxima. The Thai name for the former means tiger’s claw clam; for the latter, cat’s claw clam. Tales are told of divers being trapped between the shells of the true giant, and drowned. This has no doubt happened, but by accident. The giant clam is not anthropophagous, nor indeed carnivorous. On the contrary it is a kind of marine ‘farmer’, obtaining most of its food from minuscule marine plants which grow along its mantle edges and are exposed to light and water whenever the shells are open.