Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs.

When were sponges accepted as animals?

Scientists debate when sponges, animals belonging to the phylum Porifera, first emerged. Some think it wasn't until the Cambrian period, between 541 million and 485 million years ago, whereas others put it as early as 760 million years ago, during Precambrian times.

Does a sponge count as an animal?

A sponge is a member of the phylum Porifera. It is a simple animal with many cells, but no mouth, muscles, heart or brain. It is sessile: it cannot move from place to place the way most animals can. A sponge is an animal that grows in one spot like most plants do.