Leech Facts

As of date, more than 650 species of leeches are identified scientifically. Nearly all of us react unusually with the mere mention of leeches. But, to the surprise of all, these creepy creatures were widely used for medical purposes. In the last few decades, the popularity of leeches for medical use has increased significantly. So, what makes leeches medically important? What are interesting leech facts? Scroll down to understand the astonishing facts about leeches.

Interesting Facts about Leeches

Before going through leech facts, let's try to identify the physical characteristics of leeches. They are brown or black colored worms having a segmented body (34 segments). Leeches possess a special sucker in both ends. In majority of the species, the mouth encloses three jaws, each equipped with small teeth. Leeches move from one place to another by walking in a looping manner.

Leeches Classification: Because of their segmented body, leeches are categorized under the phylum Annelida, thus sharing phylum with earthworms and lugworms. The class of leeches is Hirudinea, which is assigned due to the presence of hirudin in the salivary secretions of leeches. Learn more on annelida characteristics.

Leeches Habitat: Leeches prefer to live in warm, swampy areas. You can find them under rocks, in marshy areas or swimming in shallow lakes and river. Many times, they are also found tightly attached to the vegetation and tree trunks of thick forests. It is assumed that one-fifth of leeches are marine and live in the sea.

Leeches Diet: Some species of leeches are parasitic bloodsuckers, attaching themselves and feeding on the blood of birds, animals and humans. You can also find scavenger leeches, foraging on decaying plants for food. Many are predators that swallow whole earthworms and insects as their diet. Leeches surviving the sea feed on small fish and other worms.

Leeches Adaptability: Unlike other annelids, leeches can tolerate very low percentage of oxygen. Some types of leeches are known to survive even when they are exposed to concentrated chemical pollutants. Another interesting leeches fact is that they can live even after losing nine-tenths of their total body weight.

Leeches in Medicine: It is the hirudin, an anticoagulant substance, present in the saliva of leeches that is pharmacologically important. Treatment that involves using medicinal leeches is collectively referred to as a hirudotherapy. Almost all species of leeches can be used for bloodletting, a method of drawing blood from a patient. Nevertheless, the most popularly used medicinal leech is Hirudo medicinalis, commonly known as European medicinal leech.

Previously, in the medieval and early modern period, leeches were frequently used for bloodletting. At present, leeches are employed to stimulate circulation (particularly in fingers, ears and eyelids), reduce blood coagulation and also, to get relief from venous pressure. The therapeutic importance of leeches is steady and continuous blood flow maintained after their detachment from the skin. Nevertheless, there are also side effects of hirudotherapy such as allergic reactions, infections at the leech attachment site and excess bleeding.

Leeches Bites: Leeches are voracious blood suckers; once coming in contact with human skin, it begins feeding on the blood. What if leeches attach to the skin? It can happen on anyone, during angling on a lake or trekking in a jungle. The tricks to remove leeches are using salt, soap and insecticidal spray over the leeches. You can also burn them with a lighted match or cigarette. But, the best way is to take hold of it properly and detach it.

Quick Facts about Leeches

• The largest leech recorded till date measures about 16 inch in length. On an average, the size of leeches is between 7 - 80 mm.
• Like earthworms, leeches are hermaphrodites, meaning that a single leech has both male and female sexual organs.
• Leech bite is painless, which is due to the anesthetic present in the saliva secretion of leeches.
• Leeches have the ability to feed in large amounts (about 5 times their body weight) and store nutrients for future use.
• Many leech species can survive for about one year after having a blood meal. They use the preserve food for survival.
• Some species (e.g., hirudo) lays their young ones in cocoons, while others (e.g., Amazon leech) keep their babies (as many as 300) in the stomach.

With these leech facts, I hope you have understood the general information about these annelids. No doubt, commercial rearing of leeches has become a booming industry in recent times with the increasing interest of leeches for medical purposes. But, it is to be remembered that the hirudo leech is included in the endangered list.