Difference between Leeches and Bloodsuckers

Leeches and bloodsuckers are blood sucking organisms. The phenomenon of sucking blood from other organisms is known as hematophagy. These animals can either be predatory or parasitic.

What are Leeches?

Leeches belong to the phylum Annelida and subphylum Hirudinea. They have a soft, muscular and segmented body that can both lengthen and contract. They are usually found in freshwater and damp environments, while some are terrestrial also. They are hermaphrodites, with both male and female reproductive organs in one body. They secrete a protein hirudin, which acts as an anticoagulant, and aids in blood sucking by increasing the flow of blood. They are a type of bloodsucker.

What are bloodusuckers?

Bloodsuckers are animals that follow blood feeding behaviour. They range from small insects like mosquitoes, leeches, lice to vampire bats and lamprey fish. They can transmit viruses and bacteria to humans, while sucking blood causing chikungunya, dengue, malaria, etc. The lamprey fish clamps onto other fishes for sucking blood, while mosquitoes have an anaesthetic in their saliva which helps in painless sucking of the blood.

Let us look at the differences between the two now.




They are small, soft, segmented worms that live by sucking blood from other organisms.

Bloodsuckers include a variety of insects, worms, mammals and fishes that practise the blood feeding behaviour.


They belong to the phylum Annelida.

They have different classifications.


Hirudo medicinalis and other species.

Bedbugs, mosquitos, ticks, lice, lamprey fishes, bats, leeches, etc.

Medical Significance

  • It was used in older times to draw blood from patients.
  • Hirudin is used as an anticoagulant to treat blood disorders.
  • A drug based on the saliva of the vampire bat has been shown to improve recovery in stroke patients.

This sums up the difference between leeches and bloosduckers.

Explore BYJU’S Biology to learn more.

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Frequently Asked Questions


How do you know if it’s a worm or a leech?

Earthworms have 30-100 segments and a muscular body, whereas leeches have 30-40 segments, and a smaller anterior and larger posterior sucker on both the ends of their body.


Do slugs look like leeches?

At first glance, they can look similar as they are both elongated and slimy organisms. But they differ anatomically and physically, while slug is a mollusk, leeches are annelids.


Are all leeches parasites?

Not all leeches are parasites, some can be predators also.


Why do leeches have 32 brains?

Anatomically, leeches have only one brain, but they are segmented in the 32 segments of their body, and hence it is said that leeches have 32 brains.


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