When looking at the forest floor, you will find a lot of dead plant matter, such as decomposing leaves, needles, and spruce cones. This matter does not stay on the forest floor for long, because it is broken down by decomposers. 

When you pick up a handful of forest soil, you are picking up thousands of small animals. Some of them are invisible to the naked eye. 

Larger animals that dwell on the forest floor include earthworms and insect larvae. They are decomposers that gain their energy by breaking down dead plant matter. Many bacteria of the forest floor also act as decomposers.

Earthworms are worms that dwell in the ground. The most prevalent earthworm species in the world is the common earthworm, which has a reddish body and can grow up to 30 cm in length. 

Earthworms like to live under the ground, but they can be seen living on the forest floor as well, especially after a rainy day. They are one of the key species of the forest. This means that their existence helps other species to thrive in a variety of ways. For example, by breaking down nutrients and mixing up the soil, earthworms help forest plants to grow.