Needs of the Earthworm

Moist Living Conditions

• Earthworms have a permeable skin. They breathe as air from the surrounding environment diffuses through their skin. Earthworms require moist living conditions or their skin will begin to dry out, and their breathing is negatively affected. Oxygen, which enters the mucous coating on the earthworm's body, passes into blood vessels where it is transported to the creature's internal organs.

Surviving Extreme Conditions

• Earthworms avoid extreme soil conditions. They are unable to function correctly when conditions become too cold, too hot, too wet or too dry. Earthworms typically dig deeper into the soil, to escape extreme conditions. During particularly dry conditions, an earthworm will twist into a ball and excrete a mucous covering around itself. The earthworm then enters a state of suspended animation, termed estivation, during which time its body functions slow down considerably. Once soil conditions improve, the earthworm becomes active again. The ability to escape temperature extremes is important to earthworms, because they are unable to maintain a steady body temperature like people can. As the earthworm's metabolic rate increases with elevated temperatures, so do its energy requirements.

Nutritional Requirements

• The different earthworm species have adapted to various soil types, ranging from those with high carbon content, to mineral soils which are low in carbon. In general, however, the earthworm feeds on decomposing organic matter, which it finds underground, and plant litter found above ground. Earthworms require soil that contains partly decomposed humus, or organic material, and need to live in areas where vegetation grows above ground level.

Oxygen Requirements and Chemical Intolerance

• Earthworms can't live in very low oxygen environments. The different species of earthworms each have their own minimum oxygen requirement, but in general, all require oxygen-rich living conditions. Earthworms are generally susceptible to toxic chemicals in the soil and tend to avoid areas where people have used fertilizers and insecticides. Worms that cannot leave such areas may die.