Thanks to Brilliant for supporting  this episode of SciShow.
Thanks to Brilliant for supporting  this episode of SciShow.

Go to Brilliant.org/SciShow to check  out their course on Scientific Thinking.
Go to Brilliant.org/SciShow to check  out their course on Scientific Thinking.

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[♪ INTRO]

As strange as it seems, animals  fall from the sky sometimes.
As strange as it seems, animals  fall from the sky sometimes.

Even ones that don’t belong there in  the first place, from fish to spiders.
Even ones that don’t belong there in  the first place, from fish to spiders.

These phenomena have been known  for centuries, but in many cases
These phenomena have been known  for centuries, but in many cases

we still don’t know where the  heck all these animals came from.
we still don’t know where the  heck all these animals came from.

But answering that question begs another one.
But answering that question begs another one.

Because we don’t always know what happens to them.
Because we don’t always know what happens to them.

I mean, yes, splat.
I mean, yes, splat.

But actually a lot more than just splat.
But actually a lot more than just splat.

In some cases, animals can actually  benefit from their aerial adventures.
In some cases, animals can actually  benefit from their aerial adventures.

While these animal rainstorms  can in fact be deadly,
While these animal rainstorms  can in fact be deadly,

sometimes animals are adapted to be rain.
sometimes animals are adapted to be rain.

So let’s look at five of the potential  outcomes for animals that become rain,
So let’s look at five of the potential  outcomes for animals that become rain,

whether they mean to or not.
whether they mean to or not.

We’ll go ahead and get the  “splat” out of the way first.
We’ll go ahead and get the  “splat” out of the way first.

It’s often a bit murky exactly  how fish and frogs end up
It’s often a bit murky exactly  how fish and frogs end up

on land and far from their home waters.
on land and far from their home waters.

But there have been enough instances  of weird rains of aquatic creatures
But there have been enough instances  of weird rains of aquatic creatures

for a lot of hypotheses to  begin circulating around.
for a lot of hypotheses to  begin circulating around.

Some have speculated they were  lifted out of their ponds and streams
Some have speculated they were  lifted out of their ponds and streams

by waterspouts, or maybe that  torrential rains flushed the animals
by waterspouts, or maybe that  torrential rains flushed the animals

from underground, and they didn’t  actually fall from the sky at all.
from underground, and they didn’t  actually fall from the sky at all.

Regardless of how they got  there, you can imagine that
Regardless of how they got  there, you can imagine that

after being caught stranded on land,  fish are not gonna fare too well.
after being caught stranded on land,  fish are not gonna fare too well.

And even if they did happen to land in  a new and ideal aquatic environment,
And even if they did happen to land in  a new and ideal aquatic environment,

they might have already been exposed  to less-than-ideal conditions
they might have already been exposed  to less-than-ideal conditions

during their travel, like getting too cold or dry.
during their travel, like getting too cold or dry.

But it’s not just aquatic animals  that rain down from the sky.
But it’s not just aquatic animals  that rain down from the sky.

There are accounts of huge  numbers of birds that have
There are accounts of huge  numbers of birds that have

dropped dramatically from above,  already dead or injured from
dropped dramatically from above,  already dead or injured from

unfortunate events like extreme  weather or forest fire smoke.
unfortunate events like extreme  weather or forest fire smoke.

But sometimes there’s actually  a strategy to their swift
But sometimes there’s actually  a strategy to their swift

and dangerous descent to Earth.
and dangerous descent to Earth.

In early 2022, hundreds of  yellow-headed blackbirds
In early 2022, hundreds of  yellow-headed blackbirds

rained down on the city of Cuauhtémoc, Mexico.
rained down on the city of Cuauhtémoc, Mexico.

Video footage of the bizarre incident  showed a massive and tight black cloud of
Video footage of the bizarre incident  showed a massive and tight black cloud of

birds rapidly drop down to the street.
birds rapidly drop down to the street.

While hundreds immediately flew back  up towards the sky, many of them
While hundreds immediately flew back  up towards the sky, many of them

died when they collided with the  road and surrounding infrastructure.
died when they collided with the  road and surrounding infrastructure.

This isn’t the only case of flocks of  birds seemingly dropping out of nowhere.
This isn’t the only case of flocks of  birds seemingly dropping out of nowhere.

It typically happens to birds who hang  out in large flocks, like starlings.
It typically happens to birds who hang  out in large flocks, like starlings.

Many causes for these unfortunate  events have been speculated,
Many causes for these unfortunate  events have been speculated,

ranging from air pollution to 5G technology.
ranging from air pollution to 5G technology.

Far more likely than that, however,  is that this is the result of a
Far more likely than that, however,  is that this is the result of a

calculated risk gone wrong as the birds  dove for cover from an aerial predator.
calculated risk gone wrong as the birds  dove for cover from an aerial predator.

There are a number of bird species that attempt to
There are a number of bird species that attempt to

escape predation in a coordinated manner.
escape predation in a coordinated manner.

They fly in a tight group, swiftly  changing direction and altitude
They fly in a tight group, swiftly  changing direction and altitude

in what appears to be a single unit.
in what appears to be a single unit.

This generally works quite well, since  predators don’t seem to like diving
This generally works quite well, since  predators don’t seem to like diving

right into the cloud, and instead try to  pick off birds that stray from the group.
right into the cloud, and instead try to  pick off birds that stray from the group.

In a last ditch effort, birds might dive very low
In a last ditch effort, birds might dive very low

towards the ground to avoid being caught.
towards the ground to avoid being caught.

If the group takes a deep dive and is  forced too low, say into a building
If the group takes a deep dive and is  forced too low, say into a building

or pavement, the coordinated  maneuver becomes catastrophic.
or pavement, the coordinated  maneuver becomes catastrophic.

While this may result in a fatal collision,
While this may result in a fatal collision,

sometimes desperate times  call for desperate measures.
sometimes desperate times  call for desperate measures.

Now, speaking of collisions, one  type of animal rain might just
Now, speaking of collisions, one  type of animal rain might just

result in a very large reptile  bonking you on the head.
result in a very large reptile  bonking you on the head.

Thanks to its balmy climate, and a  fair bit of carelessness on our part,
Thanks to its balmy climate, and a  fair bit of carelessness on our part,

in the United States, Florida is home to many
in the United States, Florida is home to many

introduced species of the reptilian variety.
introduced species of the reptilian variety.

Whether from accidental  introductions by tropical cargo or
Whether from accidental  introductions by tropical cargo or

purposeful releases of exotic pets,  some of the over 150 documented reptile
purposeful releases of exotic pets,  some of the over 150 documented reptile

introductions have reached  invasive population levels,
introductions have reached  invasive population levels,

including one very large lizard.
including one very large lizard.

The native range of the green iguana  includes Mexico south to Paraguay
The native range of the green iguana  includes Mexico south to Paraguay

and Brazil, but they’ve  been kicking around Florida
and Brazil, but they’ve  been kicking around Florida

since at least the 1960s thanks to the pet trade.
since at least the 1960s thanks to the pet trade.

Now, much of central and southern  Florida is warm enough year-round
Now, much of central and southern  Florida is warm enough year-round

for these heat-loving lizards, and luckily  for them cold snaps are pretty rare.
for these heat-loving lizards, and luckily  for them cold snaps are pretty rare.

But when they do happen they can put  iguanas and innocent pedestrians at risk.
But when they do happen they can put  iguanas and innocent pedestrians at risk.

If the temperature drops too  low during a Florida winter,
If the temperature drops too  low during a Florida winter,

iguanas have been found to  literally fall from the trees.
iguanas have been found to  literally fall from the trees.

Now, iguanas do sometimes purposely  drop from tree branches to avoid danger,
Now, iguanas do sometimes purposely  drop from tree branches to avoid danger,

but that’s not what’s happening in these cases.
but that’s not what’s happening in these cases.

Iguanas are exothermic, meaning they rely on
Iguanas are exothermic, meaning they rely on

external temperature to  maintain their body temperature.
external temperature to  maintain their body temperature.

They’re usually most active  above 25 degrees Celsius,
They’re usually most active  above 25 degrees Celsius,

so lower temperatures can  slow them down considerably.
so lower temperatures can  slow them down considerably.

And during these cold snaps, temperatures dip
And during these cold snaps, temperatures dip

as far as zero Celsius, a considerable drop.
as far as zero Celsius, a considerable drop.

This can immobilize the iguanas to the point where
This can immobilize the iguanas to the point where

they’re just no longer able  to hang on to their perch.
they’re just no longer able  to hang on to their perch.

And as you can imagine, getting  struck from above by a stiff,
And as you can imagine, getting  struck from above by a stiff,

six-foot-long lizard is not  going to feel very good.
six-foot-long lizard is not  going to feel very good.

So in these cases, there have even been official
So in these cases, there have even been official

‘falling iguana’ alerts issued to residents!
‘falling iguana’ alerts issued to residents!

Thankfully, as long as they weren’t injured  in the process, these grounded iguanas
Thankfully, as long as they weren’t injured  in the process, these grounded iguanas

can wander their way back up into their  trees once things warm up a little.
can wander their way back up into their  trees once things warm up a little.

And much like iguanas, certain  ants make their homes in trees,
And much like iguanas, certain  ants make their homes in trees,

including many species in  Central and South America
including many species in  Central and South America

that spend their entire lives way  up in the rainforest canopies.
that spend their entire lives way  up in the rainforest canopies.

These arboreal ants are well adapted  to life high up in the canopy,
These arboreal ants are well adapted  to life high up in the canopy,

with special sticky feet that help them cling  to their home tree at startling heights.
with special sticky feet that help them cling  to their home tree at startling heights.

Even so, they do occasionally lose their grip
Even so, they do occasionally lose their grip

and take a tumble if they become  dislodged or are startled.
and take a tumble if they become  dislodged or are startled.

But even in these cases where  it does start raining ants,
But even in these cases where  it does start raining ants,

you don’t have to worry about  them landing in your hair
you don’t have to worry about  them landing in your hair

while you walk by some 30 meters below.
while you walk by some 30 meters below.

That’s because they’re very good at  gliding their way back to their home trunk.
That’s because they’re very good at  gliding their way back to their home trunk.

The dramatic descents of  one species in particular,
The dramatic descents of  one species in particular,

Cephalotes atratus, has  been quite well documented.
Cephalotes atratus, has  been quite well documented.

In a study published in Nature in 2005,  researchers used video recordings and
In a study published in Nature in 2005,  researchers used video recordings and

field experiments to determine  that these falling ants
field experiments to determine  that these falling ants

hit their home-trunk target  more than 80% of the time!
hit their home-trunk target  more than 80% of the time!

Building on this, later studies manipulated  the legs and abdomens of these ants
Building on this, later studies manipulated  the legs and abdomens of these ants

to figure out how they were able to  maneuver themselves home so accurately.
to figure out how they were able to  maneuver themselves home so accurately.

They adjust their body’s  position while in rapid freefall,
They adjust their body’s  position while in rapid freefall,

spinning around to align their  abdomens towards their home trunk
spinning around to align their  abdomens towards their home trunk

before gliding over to it,  their rear end leading the way!
before gliding over to it,  their rear end leading the way!

While it does appear to be a whole-body effort,
While it does appear to be a whole-body effort,

their hindlegs seem to play an  especially key role in their ability to
their hindlegs seem to play an  especially key role in their ability to

redirect themselves towards their  home tree during these big falls.
redirect themselves towards their  home tree during these big falls.

But it’s not just this one species who  can glide their way back to safety.
But it’s not just this one species who  can glide their way back to safety.

This directed aerial descent has actually evolved
This directed aerial descent has actually evolved

numerous times within different ant subfamilies.
numerous times within different ant subfamilies.

And though they don’t all  glide in the exact same manner,
And though they don’t all  glide in the exact same manner,

this proves to be a vital  adaptation to arboreal ants.
this proves to be a vital  adaptation to arboreal ants.

If they weren’t able to  latch back onto their tree,
If they weren’t able to  latch back onto their tree,

they would fall the human equivalent  of 5 kilometers from their home,
they would fall the human equivalent  of 5 kilometers from their home,

and into dangerous, uncharted territory.
and into dangerous, uncharted territory.

And if falling ants make you squirm,  you might not want to imagine
And if falling ants make you squirm,  you might not want to imagine

numerous tiny spiders raining  down after flying through the sky.
numerous tiny spiders raining  down after flying through the sky.

But imagine a bunch of teeny tiny  baby spiders climbing to a high point,
But imagine a bunch of teeny tiny  baby spiders climbing to a high point,

letting out strands of silk, and  floating off into the distance,
letting out strands of silk, and  floating off into the distance,

sometimes hundreds of kilometers away.
sometimes hundreds of kilometers away.

This ballooning behavior is found all over  the world in different spider species,
This ballooning behavior is found all over  the world in different spider species,

and it’s often no short flight.
and it’s often no short flight.

Some spiderlings have been found as  high as four kilometers up in the sky!
Some spiderlings have been found as  high as four kilometers up in the sky!

And we’ve actually been pondering  this behavior since the early 1800s.
And we’ve actually been pondering  this behavior since the early 1800s.

Even Charles Darwin puzzled  over ballooning spiders that
Even Charles Darwin puzzled  over ballooning spiders that

landed on the Beagle while  they were out in the ocean!
landed on the Beagle while  they were out in the ocean!

Over the years there have been two main  hypotheses regarding airborne spiders.
Over the years there have been two main  hypotheses regarding airborne spiders.

Some thought it was simply the wind  carrying them to far off places,
Some thought it was simply the wind  carrying them to far off places,

while others thought that it was  electrostatic forces in the atmosphere.
while others thought that it was  electrostatic forces in the atmosphere.

And while the wind would seem  to be the obvious choice,
And while the wind would seem  to be the obvious choice,

it doesn’t fully explain why spiders  choose to balloon on calm days.
it doesn’t fully explain why spiders  choose to balloon on calm days.

Plus the multiple silk strands released  for their flight splay out like a fan,
Plus the multiple silk strands released  for their flight splay out like a fan,

and don't tangle in the wind as you might expect.
and don't tangle in the wind as you might expect.

A study published in Current  Biology in 2018 finally
A study published in Current  Biology in 2018 finally

tested the electrostatic  theory for the first time.
tested the electrostatic  theory for the first time.

And they found that while these  little spiders likely rely on
And they found that while these  little spiders likely rely on

a combination of the two factors, the  electrostatic forces played a major role.
a combination of the two factors, the  electrostatic forces played a major role.

To test this, they generated a  controlled electric field in conditions
To test this, they generated a  controlled electric field in conditions

without any moving air, and  introduced some baby spiders.
without any moving air, and  introduced some baby spiders.

The spiders readied themselves and took off!
The spiders readied themselves and took off!

Using the electric field, the  researchers were even able to
Using the electric field, the  researchers were even able to

control the altitudes of the  spiders once they were in the air.
control the altitudes of the  spiders once they were in the air.

They also found that little hairs  on their exoskeleton respond to
They also found that little hairs  on their exoskeleton respond to

changes in the electric field around them,  likely signaling to them it’s time to fly.
changes in the electric field around them,  likely signaling to them it’s time to fly.

Of course, these spiders aren’t  just flying for the fun of it.
Of course, these spiders aren’t  just flying for the fun of it.

This ballooning behavior allows these  wingless flyers to find new habitats,
This ballooning behavior allows these  wingless flyers to find new habitats,

which would otherwise be too far to crawl to.
which would otherwise be too far to crawl to.

That way, they can avoid overcrowding  and food availability issues
That way, they can avoid overcrowding  and food availability issues

that might crop up if they  all stayed in close proximity.
that might crop up if they  all stayed in close proximity.

So, maybe not all reports of  animal rains are legitimate.
So, maybe not all reports of  animal rains are legitimate.

After all, we humans tend to tell tall tales.
After all, we humans tend to tell tall tales.

But in other cases, the observations  are not only well documented,
But in other cases, the observations  are not only well documented,

but are often happening for a very good reason!
but are often happening for a very good reason!

And while some cases of animal rain can  be deadly for the poor falling creatures,
And while some cases of animal rain can  be deadly for the poor falling creatures,

other times they not only survive their  aerial drops, but might even benefit from it.
other times they not only survive their  aerial drops, but might even benefit from it.

Looking at strange things like  animals falling from the sky
Looking at strange things like  animals falling from the sky

and searching for explanations  is just what scientists do.
and searching for explanations  is just what scientists do.

And if you’re looking to train your  brain in that kind of rational approach,
And if you’re looking to train your  brain in that kind of rational approach,

you might like Brilliant’s  course on Scientific Thinking.
you might like Brilliant’s  course on Scientific Thinking.

There, you'll dispense with  number-crunching and mathematics
There, you'll dispense with  number-crunching and mathematics

in search of something more  useful: physical insight.
in search of something more  useful: physical insight.

This is just one of their  many courses recently upgraded
This is just one of their  many courses recently upgraded

to make it even more interactive than before.
to make it even more interactive than before.

They’re designed to engage your  curiosity, not ask you to memorize stuff.
They’re designed to engage your  curiosity, not ask you to memorize stuff.

And don’t worry if you’re busy.
And don’t worry if you’re busy.

Their courses are split into bite-sized  pieces so you can learn at your own pace.
Their courses are split into bite-sized  pieces so you can learn at your own pace.

Brilliant has a ton of science,  engineering, and computer science courses,
Brilliant has a ton of science,  engineering, and computer science courses,

so you can always find something new to learn.
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To get started, head to brilliant.org/scishow
To get started, head to brilliant.org/scishow

to save 20% on an annual premium  subscription to Brilliant.
to save 20% on an annual premium  subscription to Brilliant.

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