σπόγγος

Greek spongos (σπόγγος) or spongia (σπογγία) named the soft, absorbent marine object that Greeks used for bathing, cleaning wounds, and lining the insides of bronze helmets. Homer mentions sponges in both the Iliad and the Odyssey. The word has no clear further etymology — it may be pre-Greek, from a Mediterranean substrate language.

Sponge diving was one of the oldest commercial activities in the Mediterranean. Divers on Kalymnos, a Greek island in the Dodecanese, harvested sponges for centuries. The trade was dangerous — free-diving to depths of 100 feet without equipment, weighted down by stones. Many divers suffered decompression sickness. When Greek immigrants brought the trade to Tarpon Springs, Florida, in the 1900s, it became the sponge capital of the Americas.

Like coral, sponges were classified as plants for most of recorded history. John Ellis proposed they were animals in 1765, noting that sponges drew water through their bodies and expelled it through openings — a behavior inconsistent with any plant. The re-classification was slow to be accepted. Sponges have no organs, no nervous system, no digestive system. They are the most minimal definition of 'animal' that exists.

Sponges (phylum Porifera) have been on earth for at least 600 million years — predating all other animal phyla. They survived every mass extinction. Their body plan has not fundamentally changed. The kitchen sponge you buy at a grocery store is synthetic — cellulose or polyurethane foam — but its shape, its name, and its function are all borrowed from the oldest animal on the planet.