Giant Clam in the Great Barrier Reef

Common Name: Giant Clam
Family: Tridacna gigas

The largest known Giant Clam weighed in at an amazing 333kg or 734 pounds and it measured 1.4 metres (nearly 4 ft) in length.  The shells of these Giant Clams were often used as children's bath tubs and for baptismal fonts in many churches in tropical areas of the world. It was once thought that the Giant Clam could trap a diver underwater by closing suddenly on his or her foot, but this could only happen to a very slow or very careless diver and as we all know touching marine life is never a good thing to do.

This enormous shellfish is the largest and heaviest of all the living molluscs. Like all bivalve molluscs the shell consists of two valves, although in the larger giant clams these cannot close completely. The shell is extremely thick and  when viewed from above, each valve has 4 to 5 inward facing triangular projections. The mantle of the clam is visible between the two shells, and is a golden brown, yellow or green, although it may contain so many blue or purple spots that the overwhelming impression is of a beautiful iridescent colour.  A number of pale or clear spots on the mantle, which are known as 'windows' function to allow sunlight to filter in through the mantle. The mantle is completely fused with the exception of two holes or 'siphons'.  The inhalant siphon is fringed with sensory tentacles, whilst the exhalent siphon is tube like and is capable of expelling a large volume of water if the clam’s shells close suddenly.  Adult giant clams are completely sessile, unable to move from their position on the coral reef.

Back

This site is © Copyright Tim Saxon 2004-2005, All Rights Reserved

site optimised by site-pro.co.uk
Steve's free web templates