There are thousands of species of earthworms found throughout the world, with new species still being discovered and described by scientists. The exact number of earthworm species is difficult to determine, as many species have not yet been formally described or studied in depth. However, it is estimated that there may be as many as 6,000-7,000 species of earthworms worldwide. These species vary in size, color, and habitat preferences, but all play important roles in soil health and ecosystem functioning.