The natural sponges we use in our baths are actually animal skeletons. Bath sponges consist of a highly porous network of fibres made from a collagen protein called spongin. The skeletons are obtained by cutting the growing sponges and soaking the cut portions in water until the flesh rots away.
Marine animals without backbones – Te Ara Encyclopedia of New Zealand
The secret life of sea sponges
Bath Sponge, NatureRules1 Wiki
Sponges - The Australian Museum
Magical mysteries of marine sponges - ScienceDirect
Beyond the Bathtub Caradonna Adventures
Marine animals without backbones – Te Ara Encyclopedia of New Zealand
Beyond the Bathtub Caradonna Adventures
Marine animals without backbones – Te Ara Encyclopedia of New Zealand
For the love of sponges
Marine animals without backbones – Te Ara Encyclopedia of New Zealand
Marine animals without backbones – Te Ara Encyclopedia of New Zealand
Marine animals without backbones – Te Ara Encyclopedia of New Zealand