The word leech often brings up a negative vibe. These creatures have a bad reputation for sucking blood. People even use it as an insult, saying someone is clinging like a leech. So, what is the deal with these leeches? How do they suck blood without causing pain? A leech has two types of suckers on its body. The sucker at the back helps it grip and attach firmly to the skin.
The oral sucker at the front works to draw in food. Medicinal leeches, which doctors use, have three tiny saw-like jaws inside their mouths. Tiny teeth line each jaw. Once the leech attaches to the skin, these three jaws cut at the same time. That is why a leech bite leaves a mark shaped like the English letter ‘Y’.
While biting our skin, the leech injects a kind of anesthesia into the wound through its saliva. This temporarily numbs the nerves in that area. That is why we do not feel any pain when it bites. Cutting the skin is the easy part, but the real challenge is keeping the blood from clotting. The human body tries to clot the blood immediately after an injury.
If the blood clots, the food supply for the leech stops. To prevent this, the leech releases a powerful chemical weapon through its saliva. Leech saliva contains ‘Hirudin’, a potent anticoagulant. It blocks ‘Thrombin’, a protein crucial for blood clotting. Because of this, the blood keeps flowing continuously from the wound without clotting.