They are mostly pale white and small (1–4 millimetres or 0.04–0.16 inches long) crustaceans, although Limnoria stephenseni from subantarctic waters can reach 10 mm (0.4 in).

L. tripunctata is unusually tolerant of creosote, a preservative often used to protect timber piles, due to symbiosis with creosote-degrading bacteria.

[4] For defence, gribbles can jam themselves within their burrows using their uropods and block the tunnel with their rear disc-shaped segment, the pleotelson.

[5] "Enzymes produced by the tiny creatures are able to break down woody cellulose and turn it into energy-rich sugars meaning that gribble could convert wood and straw into liquid biofuel.

"[6] One particular enzyme produced in a special organ in the body of the gribble called the hepatopancreas and secreted into its gut has recently been identified and characterized: the GH7 cellobiohydrolase, LqCel7B.