How many mosquitoes would it take
to drain all of your blood?
(rock music)
♪ Science ♪
(Sigh) One hundred push-ups.
You know there aren't many sounds
more immediately annoying than the sound
of an approaching mosquito.
Because of their blood sucking ways,
these 3500 different species of ectoparasite
have become symbols of irritation and disease.
We're usually only worried with what happens
after we get bit by a mosquito.
Dang.
But what if the blood sucking itself
was the really dangerous part.
How many mosquitoes would it take
to drain all of your blood?
(upbeat music)
This thought experiment comes from
my favorite recent anime, One-Punch Man.
In the second episode of season one,
Saitama and Genos face off against Mosquito Girl,
a demon level threat who controls massive swarms
of mosquitoes.
She uses those insects to drain an entire dude
of blood, a fate that presumably would have befallen
One-Punch Man and Genos had she not been
splattered in a single swipe.
The question is still alive, though.
How many mosquitoes would it take
to drain a person completely?
Would it really take just seconds?
And is it even possible?
To answer the first part of our question,
we need two numbers,
the amount of blood the average person has,
and the amount of blood the average mosquito drinks.
Saitama here is a Japanese male of average height and weight
and the average weight in Japan is 59kg.
The average person has 77 milliliters of blood in their body
for every kilogram of mass.
So using One-Punch Man as our example,
the amount of blood mosquitoes would have to drain from him
to drink him dry would be four and a half liters.
Now the amount of blood an average mosquito drinks
varies from species to species.
But studies that I could find, put that
(whap)
put that number as anywhere between one and ten microliters
before they are replete with blood.
Dividing our two values, the number of mosquitoes
it would take to fully drain a man of Saitama's size
is somewhere between 450,000 and 4.5 million.
We have a very brute force number now,
but what would this terrible fate actually look like?
Well another study, this one on the average surface area
of the Japanese population,
gives us an equation that we can plug Saitama's stats into.
And if we do that (sigh) it gives us 1.67 square meters
of skin available to mosquitoes.
This number means that to drain all of a person's blood
for every patch of skin, literally this size,
there would have to be between
670 and 6700 mosquitoes on it.
I just drew 670 dots into the required surface area.
This is the minimum density to make this situation work.
Now imagine that, if you had this many mosquitoes on
every single square inch and centimeter of your body.
It would be like you were wearing a second skin
that was buzzing.
It would be (yells)
Still though, we are only being theoretical.
Can that many mosquitoes even fit on a person?
Mosquitoes range in length from two millimeters
all the way up to 19 millimeters,
and if we assume that the surface area a mosquito takes up
is maybe a square in accordance with its length,
to be generous,
then we can calculate just how many mosquitoes
can actually fit on a given surface area.
You can mess with the math yourself,
but I think that the only way to make this
even remotely plausible is if Mosquito Girl here
could telepathically control a swarm
of the very smallest mosquitoes
that are somehow able to drink more
than they should be able to,
because 450,000 of the smallest mosquitoes
might only need 1.8 square meters of space.
Yes, the Saitama that we're considering
has a little bit less than 1.7 square meters of space,
but I think there is some wiggle room here to make
the numbers work.
Okay?
Cool.
If we take the anime very seriously,
then there is a chance that enough
telepathically directed mosquitoes
could land on you and drain all of your blood.
But what would happen next?
Come on!
If you were drained by hundreds of thousands
or even millions of mosquitoes, it would not
be a nice or a quick way to go.
After a mosquito locates and lands on its host,
it then plunges its proboscis,
Ow!
into it and injects a little bit of saliva
that prevents the blood from clotting
and also dilates the veins and capillaries.
These mouth parts are really good at sawing through skin
and getting even deeper towards the blood.
It is highly specialized.
Ow! Genos?
Thank you!
Scientists have only recently gotten footage
of what happens next, what it looks like
when those mouth parts are probing around
inside of the host's skin looking for
a source of blood to tap into.
This is a mosquito rooting around
underneath the skin of a mouse
and as you can see, the proboscis is
incredibly flexible, which surprised scientists.
And, it's kind of gross.
As you can imply from this kind of footage,
it takes time for a mosquito to land on, feed,
and then fly away.
Look how long it's probing around in this mouse's skin.
So, it's not going to take just a few seconds
for mosquitoes to drain your blood.
Sometimes it can take up to minutes.
So death by mosquito will take much longer than
the 10 seconds it does in One-Punch Man
and we can go through that process,
second by excruciating second.
Jeez, too slow Genos.
Come on!
Imagine a few million mosquitoes all landing on you at once.
All finding sources of blood on your body to tap into
and all of the blood in your body perfectly flowing
into those mosquitoes over time without impediment.
After about 25 seconds, you will have lost enough blood
to enter stage one of shock.
Your blood pressure has remained the same
because your veins are constricting to increase
the flow rate.
Your heart is beating normally.
You're breathing normally, but you're starting to get pale.
About 25 seconds later, you will have entered
stage two of shock.
You're starting to get anxious.
You're breathing more heavily, and
your heartbeat is going way up.
Just a few seconds later and you will enter
stage three of shock.
You are now sweating.
You're breathing abnormally fast.
You're confused, and your blood pressure is dropping.
In just a little over a minute,
the mosquitoes would have drained
over 40% of your blood volume in total,
and you have entered into stage four of shock;
lethargy, extremely rapid heartbeat and breathing,
possible coma,
blood pressure failing,
death imminent.
Is my, is my hair gonna fall out?
Yes, it would take an absurd number
of somehow mind controlled mosquitoes
to drain all of your blood, but then again,
they wouldn't have to.
They'd only have to drain about 40% of it,
and then without immediate medical attention,
you'd be done for.
This reduces the number of mosquitoes needed
to make the situation work,
which reduces the amount of surface area
all those mosquitoes need,
which makes this kind of plausible,
for an anime,
which is pretty good.
Hey! Get! Out! Of! Here!
99. 100 squats.
Of course, this has all been a thought experiment.
If you really wanted to drain all of a person's blood,
then you could command a swarm of creatures
that are a lot more effective than the mosquito.
The winter tick or moose tick
is an ectoparasite of undulates like deer and moose.
I found estimates for the size of the blood meal
that these parasites take
in the one to four milliliter range,
a thousand times more volume than a mosquito drinks.
Do the math and you find that for a person Saitama's size
it would only take a little over a thousand ticks
to drain all of their blood.
And they wouldn't even have to be that close together.
This sounds horrific, and unfortunately we know
that it's actually possible.
Because of climate change, the winters
in Maine and New Hampshire
are getting shorter and shorter,
which allows these ticks to survive and feed
for longer and longer.
Last year it was reported that 70% of moose calves
in that area were dying because they were being covered
by literally tens of thousands of ticks,
which could drain dozens of liters of blood
from them over time, many times more blood
than you have in your entire body.
Scientists who find these moose calves call them
ghost moose (sigh).
It's tragic and I don't even want to show you pictures,
but ticks wouldn't even be the worst blood sucker.
Leave those moose alone!
After hanging on you for 20 minutes to an hour,
the leech can drain upwards of 30 milliliters of blood
from your body, around 10,000 times more
than a single mosquito could.
Doing our blood math again, it would only take
60 leeches spread across your body
to put you into stage four of shock,
and 150 to drain you completely,
which is a ridiculously small number.
If draining blood is the prize,
then leeches completely outclass the mosquito.
But we're still forgetting one very important fact.
It does not take a million mosquitoes to end you.
It only takes one.
What, and you're dropping my rank, too?
This is bogus!
It's not sharks, it's not snakes,
it's not lions, it's not even other humans.
Mosquitoes are the deadliest animal on earth.
Mosquitoes are so deadly because
the majority of their 725,000 victims each year
die from malaria, a disease that mosquitoes transmit.
Malaria is caused by a parasite
entering a host's bloodstream
and it affects 200 million people each year,
killing 600,000.
It makes all of the animals we're usually so afraid of
seem harmless by comparison.
Right now, our best scientists are thinking of clever ways
to deal with the malarial menace.
It could be something as simple
as a silver bullet insecticide,
or something as complicated as genetic engineering.
But however we end up dealing with the mosquito threat,
whether it be theoretical danger like we're talking about,
or otherwise, science is gonna end up
as the true hero.
To answer our initial question though,
if you could command a swarm of mosquitoes
to drain a person fully of blood like in One-Punch Man,
it would take somewhere between half a million and
five million insects to do so, even fewer
if simply incapacitating the person was the goal.
Regardless of the number, though, it would be
a long, grizzly way to go, because
that's it!
(blowing)
Science
Man, those things suck!
(upbeat music)
Like I said, we're just kind of working
with raw numbers here and we're leaving out
one thing for simplicity, which is
the more blood you take out of a person,
the lower their blood pressure is going to go,
because they don't have the same amount of fluids,
so the fluid pressure is going to be different.
So at some point, a point at which I don't know
how to calculate, there's not going to be enough
blood pressure to supply the blood going around the body
to feed all of the mosquitoes.
So there's some breaking point where you lose enough blood
that the blood pressure drops enough
that mosquitoes can't even drink from you anymore and
are you dead by then?
I don't know.
Hey, I'm just here for the anime.
Thank you so much for watching, Charlie.
If you want more of me go to alpha@ProjectAlpha.com
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