18 Leeches Facts: Discover the Truth About These Bloodsuckers

Leeches are creatures that feed on blood; hence, they are seen as nasty and unpleasant to most people. However, these creatures are also wide usages in medicine.

These creatures are related to oligochaetes, such as earthworms. Like earthworms, they have muscular and soft segmented bodies that can contract and lengthen. 

Still today, despite the development of science, the treatment of various types of health issues can be done with these leeches.

So, in this article, we will discuss some amazing facts about this unique creature known as leeches.

Amazing leeches Facts:

๐Ÿ‘‰ Leeches can be found in marine waters as well as inland freshwaters

Leeches Found In Marine Waters

Leeches can live in brackish, fresh, salt, and even on land. Leeches love to stay in still, shallow, or slow-moving water.

You cannot see these creatures in raised bogs or rushing mountain streams. Those few leeches adapted to live on land stay in the litter of tropical forests, like the Ceylon leech.

These creatures have a predatory or parasitic lifestyle. Most of them are amphibiotic or aquatic creatures.

๐Ÿ‘‰ Leeches fall under the phylum Annelida

There are more than 500 species under the phylum Annelida. Most of these have one or two suckers.

Also, almost all of them are symbionts, meaning creatures that can show excellent tolerance to various factors of the environment.

These creatures can live in different types of conditions and can colonize Earthโ€™s large areas. Along with leeches, eurytopic species include the common reed, the house sparrow, and the common bracken.

๐Ÿ‘‰ Movements of leeches in the water

Movements Of Leeches In The Water

Leeches can move in a way that is a lot similar to caterpillars. In water, these annelids move in a meandering and wavy motion. These creatures can extend their bodies with the help of suction cups.

They extend their body forward, attach themselves to the bottom with the help of the front suction cup, and then move by contracting the rest of their body.

The body color of leeches is shades of green and brown with a hint of black.

๐Ÿ‘‰ The cephalic segment of leeches

The segment of the leeches, known as the cephalic segment, comprises four segments and a prostomium.

The location of leechesโ€™ eyes is this prostomium, and their eyes may vary from just one to ten pairs of different sizes and shapes.

The position of eyes varies between different species, and some leeches donโ€™t have any eyes at all.

๐Ÿ‘‰ The body of leeches are strange

Body Of Leeches Are Strange

The body of leeches is obovate, elongated, or dorsoventrally flattened and can range in length from several millimeters to more than 30 cm.

Leechesโ€™ bodies are distinctly segmented and contractile and even taper towards the end of there are one or two suckers.

The suction cups of leeches are used to attach to the substrate, and these bloodsucking creatures can penetrate under the skin of their prey.

For sucking purposes, leeches use their strongly muscled esophagus and pharynx. The anterior sucker of these annelids contains the mouth opening.

๐Ÿ‘‰ Leeches are hermaphrodites

Leeches are hermaphrodites, and they use cross-fertilization procedures and have developed complex mechanisms to prevent self-fertilization.

Most leeches can lay their eggs in a cocoon attached to stones, plants, in the soil, or on the underside of the parent organism.

The number of their eggs ranges between 1 and 300. In those cocoons, simple development takes place, meaning no metamorphosis happens there.

In aquatic places, this cocoon is attached to an underwater surface, and the parents of one family exhibit parental care.

Some leech species nurture their offspring by carrying the young on their abdominal sides.

๐Ÿ‘‰ Number and sucking procedure of leeches

Sucking Procedure Of Leeches

There are almost seven hundred species of this annelid currently recognized. Among them, a few hundred are marine, ninety are terrestrial, and the remaining are freshwater.

These creatures attached themselves to their host with a sucker and fed on blood.

However, before that, they secrete a specific kind of peptide called hirudin to prevent the blood from clotting. Also, leeches have jaws that help them pierce their victims’ skin.

๐Ÿ‘‰ Leechesโ€™ saliva has certain properties

Leechesโ€™ saliva contains hirudin, a specific substance that can prevent blood from clotting. Their saliva also contains histamine that can cause dilation of the blood vessels.

The secretion of hirudin can cause the blood absorbed into the digestive tract not to clot. 

This enables parasitic leeches, especially medical ones, to feed โ€œin reserve.โ€ For this, the specific kind of medical leech is only required to attack its host twice a year.

This medical leech is used to treat many patients every year, and this treatment is called hippotherapy.

๐Ÿ‘‰ More than a dozen leech species from the Hirudinidae family are used for hirudotherapy

Leech Species From The Hirudinidae Family

One of the most commonly used species of leeches is Hirudo verbena, which is the Asian-Southern European one, the Hirudoorientalis, which is the Asian species;

The Hirudotrctina, the African species, and the Hirudomedicinalis, the medicinal leech, remain under strict species protection in multiple countries.

Also, in 2004, the US Food and Drug Administration approved using leeches for medicinal purposes and recognized them as therapeutic agents.

๐Ÿ‘‰ The first recorded cases of hirudotherapy

From the wall paintings dating back to the 1550 to 1292 BC or 18th Dynasty, it was known that leeches were used for therapeutic purposes.

The use of leeches in the medical field is recorded in the earliest written sources, such as the 2nd century BC by Nikander, and also from 1st century Sanskrit, Arabic, Persian literature, and Chinese sources.

The Romans gave these annelids the name Hirudo which Linnaeus used for their description.

๐Ÿ‘‰ They are still used for medical treatments

Leaches Used Medical Treatments

In modern times, leeches are used to treat various types of diseases, such as joint issues, osteoarthritis and epicondylitis, and extremity vein diseases.

These leeches are also used in microsurgery, as hirudin is an anticoagulant element that can treat several blood-clotting disorders.

๐Ÿ‘‰ The saliva of a leech contains many beneficial enzymes

The saliva of a medical leech has more than 50 beneficial enzymes. Thus, this insect is used for various types of significant therapies. Once in Russia, these medicinal leeches were used to treat hangover symptoms. 

Moreover, Napoleonโ€™s army that invaded Russia during World War II collected millions of medicinal leeches for treatment.

๐Ÿ‘‰ Leeches are segmented animals

Leeches Are Segmented Animals

Similar to other annelids, the leech is a segmented animal. However, unlike most other annelid species, the segmentation of leeches is masked by external ring markings, known as annulations. The number of these annulations varies a lot between different species and parts of the body.

In one leech species, the body surface is divided into 102 annuli. However, all species of leeches have 32 segments, known as somites, and some have 34 segments, including two head segments.

๐Ÿ‘‰ The body structure of leeches

Among the segments, the first five parts are designated as the head and also include the anterior brain. Also, here you may see several eyespots or ocelli dorsally and the sucker ventrally.

The following mid-body part has 21 segments, each containing a nerve ganglion. Also, between those parts, there are two reproductive organs: nine pairs of testes and a single female gonopore.

The last seven segments of leeches have the posterior brain and are fused to create the tail sucker of an animal.

๐Ÿ‘‰ The body cavity of leeches

Body Cavity Of Leeches

Leeches are very different from the common annelids, which are cylindrical in shape, along with a coelom or fluid-filled space.

In leeches, most of this coelom or body cavity is filled with botryoidal tissue, a loose connective tissue made of clusters of cells.

The remaining part of this body cavity has been reduced to four longitudinal channels. In the body of leeches, circular and longitudinal muscles in the body wall are supplemented by diagonal muscles, allowing leeches to use a large range of body shapes and great flexibility.

๐Ÿ‘‰ The feeding procedure of leeches

Almost three-quarters of leech species are parasitic creatures because they feed on the blood of their hosts, while the remaining species are predators.

Most species of leeches have a pharynx, which they can protrude to. This pharynx is called a proboscis. However, they may have a pharynx that cannot protrude, armed with jaws.

๐Ÿ‘‰ The respiration procedure of leeches

Respiration Procedure Of Leeches

Leeches have no respiratory organs; generally, they respire through their body wall. However, there is an exception that is in the Piscicolidae. In this species, leaf-like laterals outgrowth from the body wall and form gills. 

Moreover, some rhynchobdellid leeches have a specific type of extracellular hemoglobin pigment; however, this only offers almost half of the leechโ€™s needs regarding transportation needs; the rest happens by diffusion procedure.

๐Ÿ‘‰ The bites of leeches

Bites Of Leeches

The bites of leeches are usually more alarming than harmful. However, some people have anaphylactic or severe allergic reactions and require medical care.

Some symptoms of these reactions include an itchy rash or red blotches over the body, dizziness, swelling around the eyes or lips, and difficulty breathing.

After being satiated on blood, leeches will detach and fall on its own, which may require twenty minutes to several hours.

Also, leeches could act as vectors as protozoa, viruses, or bacteria from previous blood sources may survive within a leech.

Hence, leeches are a specific type of annelid that can benefit and harm us humans.

At the end of this article, we learned about 18 really amazing facts about this remarkable creature called leeches.

These facts offer us a clear picture of this unique annelid of our ecosystem. To collect some more amazing facts, you may visit our website.

Was this article helpful?

Join our active Facebook group for creative and fun activities, games, and other child development ideas.

Leave a Comment