Sleepy Sponge Crab

Tumidodromia dormia is the largest species in the family Dromiidae, at up to 200 millimetres (7.9 in) across the carapace for males, and up to 172 mm (6.8 in) for females.

Tumidodromia dormia has a widespread distribution in the Indo-Pacific region. Its range extends from East Africa (including Madagascar, the Seychelles and Mauritius) and the Red Sea through the Malay Archipelago, south to Queensland (Australia), north to China and Japan and as far east as Hawaii and French Polynesia. It is mostly found in shallow waters, with the deepest record being 112 m (367 ft).

Like other related crabs, T. dormia camouflages itself by carrying a sponge on its back, which it cuts to size with its claws, and then holds in place with its last two pairs of legs. Instead of a sponge, T. dormia has occasionally been observed carrying other materials, including a hollow piece of wood, and the sole of a discarded shoe.

Little reproductive data is available for T. dormia. One ovigerous (egg-carrying) female from the Marquesas Islands was carrying around 130,000 eggs, each 0.5 mm in diameter.