Vampire Bats

Created April 2009
Last updated January 2013

• 

  Photo Ross Baker Surrey Bat Group

• The common vampire bat is found from Mexico to Argentina and Chile.
• There are only three species of vampire in the world
• 

  Photo by Daniel Hargreaves

  Only one of these feeds on human blood

• Vampires use echolocation to find their prey. They are nippy movers and can crawl along the ground between prey.
• Once on their prey they use heat sensors on their nose leaves to detect where capillaries flow nearest to the surface.
• Vampire lick their prey before feeding. Their saliva contains an anaesthetic so that their prey is unaware they are being fed on and an anticoagulant which prevents blood clotting so they can feed for longer.
• This anticoagulant has been isolated  and chemists have now synthesised a chemical called draculin which is used to treat stroke victims More
• How do you extracxt saliva from Vampire bats. The answer apparently is to use anti glaucoma medication on them – which has the side effect of making people – and bats – salivate copiously.
• Desmondus rotundus can eat about 60% of their body weight in blood per day. A 35 gram bat can drink 25ml of blood in a single meal – which is why they got the name “rotundus”.
• They spend about twenty minutes feeding on their host if undetected. Their saliva contains a local anaesthetic which makes it less likely they will be noticed.
• 

  Photograph Daniel Hargreaves

  They use their incisors to open a wound, but because their food is liquid have fewer teeth than other bats.

• 

  http://www.arkive.org/common-vampire-bat/desmodus-rotundus/image-G16542.html

  They don’t suck blood; they just drink what oozes out of the wound.

• Their tongues are grooved to speed blood flow from mouth the stomach.
• A typical female vampire bat weighs 40 grams and can consume over 20 grams (1 fluid ounce) of blood in a 20-minute feed. Their stomachs are unusually large and have a rich capillary supply

• They only keep the red blood cells. Their stomachs and kidneys are designed to filter prey blood plasma out of the body before they take off after a meal.
• So vampires produce large quantities of urine
• 

  http://www.bio.davidson.edu/people/vecase/Behavior/Spring2002/perry/altruism.html

  Female vampires are altruists. On returning to their roosts, if a roost mate has not fed, they will regurgitate their latest blood meal to help their sister out, but will expel a sister if she later fails to reciprocate.

• New research has shown they will feed non relatives as well  see

  http://rspb.royalsocietypublishing.org/content/280/1753/20122573.full
  For a brief sumary see  http://socialbat.org/

  
  David Attenborough film clip

• The vampire bat is one of the few known bats capable of walking, jumping and hopping. This is accomplished by folding its wings in such a way that the animal literally walks on its thumbs. This behaviour is important because it allows the bat to maneuver on the ground and to climb on their host

• Vampire bats on a specially designed treadmill have clocked an impressive 1.2 metres per second.
  (Source New Scientist News 19 March 2005).Click here for more information and an amazing picture of a running bat or try looking at this video

• Vampires save time when feeding by looking for animals they have fed on before, because it is easier to pick a scab then make a new wound. The sides of their tongue act as rasps to reopen the original wound’ How do they recognise old prey? They recognise the pattern of their breathing  For more information click here

• Vampire bats use infrared sensors on their lips to locate blood vessels in their prey, scientists have discovered. The specialised nerve cells are similar to the pain-sensing cells in the human tongue, skin and eyes, which allow us to sense the sting of chilli peppers and high temperatures. More

See film of a vampire feeding on a seal pup made by the BBC Natural History Unit

http://www.arkive.org/common-vampire-bat/desmodus-rotundus/video-08d.html (slow to download.
In November 2011 , two  of us went on a bat trip to Nicaragua and fulfilled a life time’s ambition to see vampires.

 

 

This female shows why the vampire bat is called “rotundus” We caught her just after she had had a good feed. Vampires urinate copiously son after feeding to reduce their body weight . She hadn’t had a chance to when we caught her.

Note the gland under her chin, we are not sure what this is for but found it on a number of bats -le and female. If you know why they are there, please let us know.

 

 

This gent had been less fortunate on the feeding front In this photo  he looks positively benevolent, but he was handled extremely cautiously by very experienced bat workers.

You can see how his thumb is  greatly enlarged to help him crawl on the ground.

When showing his displeasure at being captured, he emitted a quite blood curdling cry a bit like a snarling dog.

 

 

An excellent website about  research into vampire bats is at http://socialbat.org/

 

 

 

This photo gives a  pretty good idea of how sharp his teeth are.

It is a front ones that break the skin

 

 

 

In 2012 4 of us were lucky enough to go on another Trinibats expedition and saw white lined vampire bats. You can read about it here 2012-7-vampire bat

 

Film on You Tube

Captive white lined vampire trying ( and failing ) to elicit food sharing

Daniel Hargreaves@film of white line vampires in a hollow tree. Note the male sefending his harm by flapping his wings at the intruder (Daniel in this case.)