How do earthworms breath?
Earthworms breathe in the same way as their aquatic ancestors. They don’t have lungs, but instead breathe through the skin. In order for gas exchange to take place this way, the outermost layers of an earthworm are thin and must be kept moist. Mucous is excreted onto the skin to keep it moist. It is also wet by body fluid which is excreted through ‘dorsal pores’ located along the dorsal (back) midline in the grooves between the segments. This need for moisture restricts their activities to a burrowing life in damp soil. They emerge only at night when the evaporating potential of the air is low, and retreat deep underground during hot, dry weather.
