Bath Sponge

The bath sponge (Spongia officinalis) is a Mediterranean sponge whose soft skeleton of protein fibers (spongin) was harvested for thousands of years for washing and padding. Natural sponge fishing shaped communities from Greece to the Florida coast.

🧬 Field Guide Specimen: Open Bath Sponge in the CRV Science Field Guide to log the specimen, see its place among the Metazoa lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

Unlike calcareous and glass sponges, bath sponges have no mineral spicules. Their skeleton is a mesh of spongin, a form of collagen, which makes them soft and elastic. After harvest, the living tissue is rotted away and the skeleton cleaned.

Sponge divers from the Greek islands founded a sponge fishery in Tarpon Springs, Florida, in the early twentieth century. Disease and overharvest devastated Mediterranean and Caribbean sponge beds in the twentieth century, and synthetic sponges largely replaced the natural product.

Sponges produce many bioactive chemicals. Nucleosides isolated from a Caribbean sponge in the 1950s led to the cancer drug cytarabine and the antiviral drug acyclovir, and sponges remain a source of drug leads. See Cancer.