They are notorious for boring into (and commonly eventually destroying) wood that is immersed in seawater, including such structures as wooden piers, docks, and ships; they drill passages by means of a pair of very small shells ("valves") borne at one end, with which they rasp their way through.

[1] Carl Linnaeus assigned the common name Teredo to the best-known genus of shipworms in the 10th edition of his taxonomic magnum opus, Systema Naturæ (1758).

Where they leave the end of the main part of the body, the siphons pass between a pair of calcareous plates called pallets.

They are borne on the slightly thickened, muscular anterior end of the cylindrical body and they are roughly triangular in shape and markedly concave on their interior surfaces.

[7] Shipworm anatomy reveals the typical organs of a bivalve mollusk, although with dimensional or positional peculiarities due to the thinness and length of the occupied space.

Normally, the shipworm's body fills the entire length of the gallery, but the anterior region can retract itself slightly with respect to the latter's extremity.

[14] The longest marine bivalve, Kuphus polythalamia, was found from a lagoon near Mindanao island in the southeastern part of the Philippines, which belongs to the same group of mussels and clams.

The existence of huge mollusks was established for centuries and studied by the scientists, based on the shells they left behind that were the size of baseball bats (length 1.5 metres (4 ft 11 in), diameter 6 cm (2.4 in)).

[15][16] The bivalve is a rare creature that spends its life inside an elephant tusk-like hard shell made of calcium carbonate.

Scientists found that K. polythalamia cooperates with different bacteria than other shipworms, which could be the reason why it evolved from consuming rotten wood to living on hydrogen sulfide in the mud.

[citation needed] The scientists are planning to study the microbes found in the single gill of K. polythalamia to find a new possible antimicrobial substance.

[17] However, the origin of T. navalis remains uncertain due to the widespread usage of ships in global trade and the resulting spreading of shipworms.

In the Baltic Sea, free-floating piles carved by shipworms can be observed floating hundreds of kilometers away from the original wooden structures.

[20] Shipworms greatly damage wooden hulls and marine piling, and have been the subject of much study to find methods to avoid their attacks.

In a letter from the Navy Board to the Admiralty dated 31 August 1763 it was written "that so long as copper plates can be kept upon the bottom, the planks will be thereby entirely secured from the effects of the worm."

In 2009, Teredo caused several minor collapses along the Hudson River waterfront in Hoboken, New Jersey, due to damage to underwater pilings.

[21] In the early 19th century, engineer Marc Brunel observed that the shipworm's valves simultaneously enabled it to tunnel through wood and protected it from being crushed by the swelling timber.

[20] In the Norse Saga of Erik the Red, Bjarni Herjólfsson, said to be the first European to discover the Americas,[24] had his ship drift into the Irish Sea where it was eaten up by shipworms.

It is prepared as kinilaw—that is, raw (cleaned) but marinated with vinegar or lime juice, chopped chili peppers and onions, a process very similar to shrimp ceviche.

[27] Similarly, the delicacy is harvested, sold, and eaten from those taken by local natives in the mangrove forests of West Papua and some part of Borneo Island, Indonesia, and the central coastal peninsular regions of Thailand near Ko Phra Thong.