Many of the organs that humans possess are also found in earthworms, which are actually a type of higher animal like humans.
The major difference is that it has no eyes. There is a theory that it was named "blind" → "me-mezu" → "memezu" → "earthworm" because it is a creature without eyes. Some regions still call it "memezu.
Some researchers have identified 118 species in 8 families, while others have identified 7,000 species.
The size of earthworms varies from less than 1 mm to as large as 45 cm for the "Siebold's earthworm," which lives in central Japan and westward.
The Megascorides australis, which lives in Australia, is said to be the world's largest species at 3.5 meters.
The main functions of earthworms are "soil improvement" and "food chain".
Earthworms feed on soil, digest and absorb organic matter, microorganisms, and small animals contained in the soil, and excrete them as granular feces.
Soil-borne earthworms are considered to be more effective in soil improvement than surface earthworms, and the two types of terrestrial earthworms commonly found in and around fields are the Diptera and the Thrushidae. In Japan in particular, the family Phormiidae are more abundant and are found mainly in the soil. The family of the earthworms is the family of the striped earthworms, and it is these worms that are used in composting and garbage.
The food and habits of the Dipterocarpaceae and the striped earthworms are different.
The family Dermacentridae is characterized by a body length of about 10 cm, which is slightly larger than that of the striped earthworm, and is the most common type of earthworm found in the field. They live by digging holes in the ground and making burrows, so the earthworms that appear when plowing the fields are basically this type of earthworm family. The Phthomidae feed on the surface layer of the soil and soil containing organic matter, and continue to move through the ground while producing feces rich in nutrients. The earthworms thus cultivate the soil, increasing aeration and drainage and creating fertile soil. The life span is about one year, and their reproductive capacity is weaker than that of the striped earthworm.
The striped earthworm is characterized by its body length of 5 to 10 centimeters, slightly smaller than the Diptera family, and has a striped pattern on its body. They tend to live in moist areas with a lot of organic matter, such as in and around compost rather than in the soil, and they do not dive very deep to live. They also like to eat food scraps and decaying organic matter, which the Diptera family does not eat very often, and they do not make burrows, so they have no problem stirring up compost, making them suitable for composting. They are also more fertile than fucoid worms and have a long life span of about two years. Striped earthworms used as fishing bait are sometimes called pheasants in fishing terminology, because they produce yellow blood (yellow blood) when the hook is pierced, which is one way to distinguish them from furtive worms.
They are also at the bottom of the food chain in the animal kingdom and play a major role as important food for many animals, from small animals such as insects and moles to medium-sized species such as birds, and even larger species such as wild boars and badgers.
When earthworms inhabit soil contaminated with heavy metals, pesticides, and other chemicals, they bioaccumulate these contaminants and may cause poisoning in predators. The earthworms themselves can survive extremely high concentrations of contamination that would kill their predators and become poisoned.
For this reason, caution should be exercised when wild-caught worms are eaten by humans, as birds and fish that eat such worms may further bioaccumulate in their bodies, causing harm back to humans in a roundabout way.
In the United Kingdom, this bioaccumulation is being used in reverse to clean up soil contaminated with heavy metals. Earthworms are also widely used for other purposes, such as herbal medicine, animal feed, foodstuffs, and liquid fertilizer.
There is some folklore about earthworms, and it has long been known that dogs like the smell of dried earthworms, which is said to have the same effect on cats (or cats in general) as matatabi.
In the manga "Kamui Gaiden" and "Sasuke" by Sanpei Shirato published in the 1960s, "Inuman" is introduced as a kind of item used in ninjutsu. When surrounded by enemies, he would use Inuman to call in a large number of wild dogs and then take advantage of the confusion to escape. Inuman is said to be made of earthworms (a sludgy liquid made by grinding a large number of earthworms, or dried earthworm powder?) (a sludgy liquid made by grinding large quantities of earthworms, or dried earthworm powder?
It's only an earthworm, but it's an earthworm.
The more you study them, the deeper and more interesting their world becomes.