Animals / General / Nature

The blood-sucking leech

Sipping your favorite beverage either during the summer or during winter is something we all do – chilled juice or hot chocolate. The pleasure one gets as the yummy beverage climbs through the straw and reaches your taste buds can be a very satisfying experience. Well, that is what some other organisms like mosquitoes and leeches do as well. Their tasty beverage however is the blood of the animal or human they feed upon. Sounds gross? Let us learn more about it.

Leeches are segmented worms related to the farmer’s friend – the earthworm (strange that one feeds on soil and the other on the farmer’s blood!!!) and are mainly found in tropical areas. They climb up the legs of unsuspecting farmers, hikers and other people who venture into their territory and feast upon their blood. This they do so in such a painless manner that the victim does not even realise that they have something sucking on their blood clinging to their body. That is very clever of them since if it were to be very painful, then they stand a greater risk of being squashed the very instant they start feeding. Most leeches have suckers with which they latch on to the host or rather prey while they feed. Then they use their powerful jaws with tooth like projections to make an incision or cut on the skin after which they relax and start enjoying the feast. Some leeches have proboscis like extensions which they push into the prey just like a straw and suck the blood.

Now as you all know, when we get a cut on our body, blood comes out initially after which they clot. This is nature’s way of protecting humans and animals from bleeding to death. The blood forms a gel like clot in which many factors in the blood are involved and they seal the incision thereby preventing further bleeding. The clever leech does have a solution to overcome this obstacle as well. It secretes a chemical called ‘hirudin’ which when in contact with the blood of the prey prevents it from clotting. The leech thus continues to suck on the liquid blood as long as it wishes to. Isn’t that a smart move?

This chemical made by the leech has proven to be a boon for mankind. Synthetically made hirudin is used widely in medicine as an anti-clotting agent. Leeches have also been used in traditional medicine for a type of therapy called blood-letting. It is believed that removing the ‘bad’ blood using leeches may help in curing some type of diseases. This has been subject to a bit of criticism by modern medical systems and is not used much these days.

Meanwhile let the leech enjoy its meal while we reflect upon how other organisms have evolved methods to fill their tummies….



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