Sucking blood for a living

Posted by John Blatchford Feb 1, 2007

I put this article in my 'general' section because all my sub-categories contain examples of blood-sucking animals, and I needed to go outside my own section to include the Vampire Bats of South America, and to be able to mention the birds.

Many of these animals are important vectors of diseases - of humans, their pets and their livestock. They are therefore of great economic importance and a lot of research has been done on many.

All 'blood-suckers' face the same problem: blood is designed to clot as soon as it leaves the blood vessels! They have all had to develop 'anticoagulants' to avoid clogging up their mouthparts with clotted blood, and many of these chemicals are proving useful in modern medicine Another problem they encounter is that their host animal does not usually like being bitten! So they have had to develop' local anaesthetics' as well as 'anti-coagulants'. These too are the subject of active medical research.

Most animals that drink blood work at night, so they have had to develop special senses to find their prey. Most are able to follow very slight gradients in carbon dioxide concentrations to locate living animals, and some can detect body heat. Vampire Bats have infra-red detectors very like some snakes - they have even developed special regions of the brain to process this information which turn out to be remarkably similar to analogous structures in the snake brain.

Not really relevant - but I live very near Whitby (North Yorkshire) where 'Dracula' was written :-)