How did scientists decide that sponges were animals when they don’t have a mouth, eyes, brains, any organs or moving parts? The cells that make up the body of sponges are like animal cells and not like plant cells. When a sponge dies it smells like a decaying animal.
The dead brown or grey sponges found on the beach are the remaining skeletons. Live sponges are often very colourful. Only a few sponges are soft enough to be used for washing.
The skeletons of most sponges feel more like sandpaper.
They need to be attached to something solid such as rocks. Sponges have small holes over their body so water can pass into it. Many of the cells in a sponge have tiny but long whips. The thousands of cells working together use their whips to make water flow through their bodies. Other cells are able to filter out microscopic items of food which are digested by the cells. The water exits out of larger holes. A sponge the size of a coffee mug can have more than a thousand litres of water pass through it in a day.