Sunday 7 August 2011

Common Vampire Bat

Image: JLplusAL via Flickr
The stuff of nightmares. A furry, ferociously fanged, flying fiend who likes nothing better than to guzzle down the warm, vital fluids of other beasts. The Vampire Bats are the only mammals who feed exclusively on blood. I hope they don't expect a medal or something.

Common Vampire Bats have a whole host of adaptations to help them in their nefarious night-time deeds. The ability to fly is a great start. I know that I would personally be absolutely furious if I found something drinking my blood, so a little 10 cm long bat better be ready when I start swinging my own bat through the air like a madman. Or at least a very angry man.

Common Vampire Bats spend their days sleeping in dark places like caves, tree hollows, old wells and buildings (I'm sure derelict asylums built on ancient Indian burial grounds are favoured). All the scary, haunted, horror places. They live in colonies, sometimes with thousands of individuals, throughout South and Central America. They awaken at night. Time to feed.

So, let's journey with a Common Vampire Bat.

Image via Wikipedia
Swooping out of a stinking cave we are glad to be greeted by the air of the nocturne. That cave really does stink.

We use echolocation just as other bats do. This involves shrieking into the air and building up a picture of our surroundings based on the echoes that come back to us. I probably wouldn't call it "shrieking" if it was anything other than a Vampire Bat, but it is a Vampire Bat so... I'm not gonna say "squeaking", anyway.

The truth is, Vampire Bats don't have as good echolocation skills as many other bats, but they do have better eyesight to compensate. They can spot a promising host from over 100 metres away. Their hearing is even better, and the sound of breathing seems to be their main way of discovering prey.

We aren't overly choosy. Horses, cattle, dogs... humans. Any mammal will do so long as it's fast asleep and we can feed in peace. We have our preferences, but you don't get "Common" added to your name by being picky about who's blood you're willing to drink. Once you've decided to drink blood, well... that's half the battle, right?

Image by Robertsphotos1 via Flickr
We now land. We can land straight on our host or we can land a small distance away. Vampire Bats are bat superstars when it comes to walking on the ground. Their speed and agility on terra firma leaves other bats looking like clumsy oafs. Eat your hearts out you other bats! Just leave the rest for me.

In any case, we now reach our great, big, bottle of claret. We just have to open it up and enjoy. Luckily, our nose is armed with thermoreceptors that sense heat beneath the skin of our host. This is where the blood is, and where there is more heat there is more blood closer to the surface.

Once we pick our spot we prepare the area. Using our teeth to shave away the fur gives us access to the skin and ensures blood doesn't get clogged up all over the place. No need to cause a mess.

Image via Wikimedia
We don't use our incisors for this, though. Those fellas are kept for another purpose. While other animals use their incisors for silly things like biting into apples, ours are razor sharp. They cut, and they pierce. And so that's what we do.

The red stuff flows and we inject our saliva into the wound. Sure, it adds insult to injury but it's nothing personal, it simply stops the blood from clotting and the blood vessels from constricting. We lap up our fill.

A Common Vampire Bat weighs about 57 grams (2 oz) but that can double in one half hour feed. The stomach immediately absorbs the blood plasma and takes it to the kidneys, leaving the nutritious red blood cells behind. Two minutes after they start feeding they already pass out the plasma through urine, making space for yet more blood. This stuff just goes right through me!

When we're finished, we leap into the air and fly into the night. Within two hours of leaving the roost we are back, resting and digesting.

The whole process will be repeated tomorrow, and if not tomorrow then the day after. We Vampire Bats need to eat every two days and once we find a good host we return to it night after night. Our urine serves as a marker to other Vampire Bats and we will chase away anyone who tries to feed on our property. It's a good thing we are so family orientated, then. Oh yes, everyone hears about the blood and the biting, but what about the bonding?

Common Vampire Bats live in a harem system, with one male defending numerous females. The females will rarely mate with any other male even if they get an opportunity to. Sometimes several males will defend one roost, in which case the alpha male will father at least half the offspring, the second male will have the second most and so on down the ranks.

Image: Phil Myers
Females give birth to one youngster at a time, feeding it only milk for 3 months and then a mixture of milk and regurgitated blood. After a while, mother and child will fly out to find food together even though it takes 9 months for a young Common Vampire Bat to be fully weaned. It probably takes them that long to accept the idea of drinking blood for a living.

Female Common Vampire Bats have very strong bonds. They groom each other and look after and even feed each others young. If a mother dies, another one will adopt the orphan. Vampire Bats are thought to be the only bats to do this.

They sometimes even share food. A hungry Vampire can beg for food from a friend and receive some tasty regurgitated blood. Hopefully, she will remember this and return the favour if the time comes.

This cooperation helps the whole colony combat starvation, since getting a blood meal every day or two can't always be easy.

Next time you see, hear or... feel a Common Vampire Bat, think not of just her vampiric ways. Think also of that same belly-full of blood as it is lovingly regurgitated into the throats of her children and sistren. Surely, such an image of caring and sharing can only bring warmth to one's heart. And a nice, warm heart is something they'll appreciate next time they see you.

Image via Wikipedia
The Common Vampire Bat; lover, mother, friend, blood sucker.


TexWisGirl said...


well, if i ever wanted to live in a commune, raising my child and perhaps someone else's too, this would be the place... i'm just all warm and fuzzy feeling now...

Joseph JG said...

I agree! It all sounds lovely. Almost all. Just a few details to iron out.

Crunchy said...

So it turns out they don't suck after all. They just shank you with their teeth, spit in the wound, lap up your blood and pee all over you. Kind of reminds me of university.

Bats really are neat critters. It's really a shame they're all so filthy. Seriously, bats, the cave wouldn't smell so bad if you'd just take that outside.

Joseph JG said...

Gosh, your university sounds... great! At least it's not a stinking cave.

Crunchy said...

That really depends on who you ask. ;D

Meg said...

I think vampire bats are really cute--just look at that little face! Especially in the first picture, batty just looks so very happy!
Now that being said, I wouldn't want to encounter one. I'm sure they're decidedly less cute as they gorge on blood. lol

Joseph JG said...

Hahah! I can see what you mean. I find their facial expressions hilarious!

Drhoz said...

They're also serious vectors of Rabies.

Joseph JG said...

That'll be on the down side, I think.