Leeches

Leeches have been used in medicine for centuries. After being almost forgotten for a while, they are now being used more frequently again.

Characteristics

What do leeches look like?

Leeches belong to the class of best worms and there to the order of leeches and suborder of the jaw flukes. They belong to the annelid worms and are related to the earthworm. Leeches consist of 32 body segments. However, the externally recognizable sections do not correspond to the internal body segments.

There is a suction cup at the front and at the rear end, which consists of several body segments. With the rear suction cup, leeches hold on to the ground, the front contains the mouth opening and is used for sucking. There are three jaws and about 80 calcareous teeth in the mouth.

Leeches are not round like earthworms. They have an oval body cross-section. Its back is dark green and there are three longitudinal brown stripes on each side of its body. Adult leeches are up to 15 centimeters long when stretched out.

Where do leeches live?

Leeches are common all over the world. Most live in freshwater, only a few in the sea. Leeches can only survive in a moist environment. They mostly frolic in freshwater, i.e. in pools, ponds, and puddles, but also in slow-flowing waters. The water must have many plants and be very clean. And of course, it has to be deep enough so that it doesn’t freeze over in winter and the leeches can survive there.

What types of leeches are there?

There are around 600 different species of leeches in the world. Depending on the species, they are between half a centimeter and 30 centimeters long and feed on the blood of various animals.

How old do leeches get?

In the laboratory, leeches can live up to 20 years if they are kept well. That is a very old age for such a small animal.

Behavior

How do leeches live?

The leech is officially called “medicinal leech” because it has been used in medicine for centuries. However, only leeches that have been bred in the laboratory are used for this purpose. To suckle, the leeches hold on to the skin with the rear suction cup and look for a suitable place to bite with the front suction cup.

When sucking, they put various substances into the wound. They inhibit blood clotting, fight inflammation and relieve pain. That is why leeches are also used on humans. They are mostly used to treat blood clots and bruises as well as varicose veins and phlebitis, rheumatism, and arthrosis. Recent research shows that leeches have a very beneficial effect on joint inflammation and relieve pain better than many painkillers.

Leeches can swim very well, but they are also quite agile on land. To do this, they use their suction cups, with which they cling to the ground and thus move the body bit by bit. For the layman, they can look like a fat earthworm from afar.

How do leeches reproduce?

Leeches are hermaphrodites, meaning each animal has male and female reproductive organs. Usually, two animals fertilize each other. To reproduce, leeches need a body of water with a constant water level. Fertilization takes place between April and October. A leech lays up to 30 eggs in a cocoon in the moist bank soil so that they cannot dry out. After about six weeks, the young leeches hatch. They measure only 16 millimeters. Only at the age of about four years can leeches be used for medicinal purposes.

Care

What do leeches eat?

Leeches are parasites, which means they live on the blood of other animals. Young leeches first feed on small animals in the water, which they eat. But they also suck blood from frogs, toads, and fish. Adult leeches prefer to feed on mammals or humans. The more blood they suckle from warm-blooded animals, the sooner they become sexually mature and the more eggs they lay.

First, leeches attach themselves to the animal’s skin and bite it open. Because they also release a natural painkiller into the wound, this bite doesn’t hurt. The animals then suck blood for up to 30 minutes. They can absorb five times their body weight

When sucking, leeches suck in the blood and excrete the water it contains through their skin. Once they have saturated themselves, they will fall off again of their own accord.

Leeches can store the sucked blood in their stomach for a long time and digest it within several months. This can take up to 18 months.

Keeping leeches

Leeches are kept and bred in medical laboratories.