A bite-size answer to the question: How and why do leeches suck your blood?
Leeches are segmented worms belonging to the phylum ‘Annelida’. The majority live in freshwater surroundings, though some species can be found in sea and land environments. Most (but not all) are ‘hematophagous’ or, to put it another way, bloodsuckers! So how - and why - do these vampiric type worms suck your blood?
Well, firstly, a leech bites into the skin and then attaches its sucker (they actually have two suckers – one at each end) around the wound. After attaching itself it secretes an anticoagulant enzyme called
‘hirudin’ into the bloodstream to prevent clotting. This enables the leech to suck without hindrance. The blood is then drawn into the leech’s digestive system which contains a large kind of sac where it can be stored for a number of weeks.Contrary to popular belief, not all leeches rely solely on blood for survival. Some eat smaller invertebrates (typically whole!) whilst others will polish off the remains of decomposing organisms. But blood is very nutritious and, by consuming and storing up
to 3 times their normal body weight in one go, sucking blood allows the leech to survive for long periods of time without food.Leeches aren’t the bad guys many think them to be and are actually pretty harmless. In fact, leeches have been historically used (records date back to 500 BC) in a clinical capacity to remove blood from patients. And they are still used today in some countries to help the flow of fresh blood to injured areas of the body and reduce tissue swelling.
So there we go... a bite-size answer to the question how – and why - do leeches suck your blood.
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The author originally published this article here: http://scienceray.com/biology/how-and-why-do-leeches-suck-your-blood/