Giant clam

Tridacna gigas, the giant clam, is the best-known species of the giant clam genus Tridacna. Giant clams are the largest living bivalve molluscs. Several other species of "giant clam" in the genus Tridacna are often misidentified as Tridacna gigas. These clams were known to indigenous peoples of East Asia for thousands of years and the Venetian scholar and explorer Antonio Pigafetta documented them in a journal as early as 1521. One of a number of large clam species native to the shallow coral reefs of the South Pacific and Indian oceans, they may weigh more than 200 kilograms , measure as much as 120 cm (47 in) across, and have an average lifespan in the wild of more than 100 years. They also are found off the shores of the Philippines and in the South China Sea in the coral reefs of Malaysia.

Source: Wikipedia