In the natural world,
you need to be smart...
..to stay alive.
But we're only just discovering that some animals are brighter
than we ever imagined.
I've never failed to be impressed by nature's sheer ingenuity.
Now, brand-new science, using innovative techniques
and the latest technology,
is revealing some surprising brainboxes.
You can get bees to learn almost anything.
Researchers across the globe are uncovering the mind-blowing tricks
and clever strategies that give certain species the upper hand...
It is an animal showcasing its intelligence in front of your eyes.
..as they build their homes...
..navigate their world,
and raise their young.
It's time to get inside the minds of nature's savviest species.
But I warn you, there's going to be a few surprises
and some controversial candidates,
but, most importantly, it's going to give us an opportunity
to learn from these animal Einsteins,
and that's really exciting.
In this episode, we'll discover the clever methods that animals
use to travel from A to B,
and how they find their way.
We'll learn blue whales know exactly where to refuel,
as they migrate thousands of miles,
how spiders and snakes can actually fly,
and how dung beetles use the Milky Way to navigate.
In the journey of life, animal travellers need mental agility,
as well as endurance, to reach their destinations safely.
I'm starting with an epic wayfarer, an animal that's enabled us
to cross the harshest of landscapes for thousands of years.
Now, there are a number of very famous long-distance animal travellers,
but there's one that comes with a reputation for being strong,
but also a bit spitty.
I'm talking about the camel.
And they've done a lot of travelling over the years,
because we domesticated them over 4,200 years ago
and they were famed for their caravans along the Silk Road.
Meet Baxter and Bertie and look at them, they are absolutely
magnificent and, having evolved in the Central Asian deserts,
they have all sorts of adaptations for that environment.
Keeping the sand out are their very long eyelashes and, you know,
if they do get sand in their eyes, just like birds, they've got
a nictitating membrane, a third eyelid,
which sweeps across to clear the sand out of their eyes.
Look at their feet.
Broad and wide, for spreading their weight,
as they travel across the sand.
Now, the humps... When I was a kid, many years ago,
my mother mistakenly told me that they were water storage organs.
Not at all.
They're full of fat, but what's interesting is
that when that fat is metabolised,
for every gram that they do metabolise,
they can recover a gram of water,
so, indirectly, they are water storage organs.
They are absolutely remarkable and there's one last thing
I have to tell you, and that is that...
HE SNIFFS ..they smell fantastic!
They really do. I love the smell of a camel.
Bertie and Baxter are two-humped Bactrian camels, well adapted
to their original home in the harsh Gobi Desert of China and Mongolia.
Their equally hardy cousin, the single-humped dromedary, was also
domesticated and used to transport goods and people,
especially in arid parts of Africa and Asia.
These powerful ungulates can cover 25 miles or more daily.
Led by an adult male,
Bactrian camels navigate across featureless terrain in search
of grazing and migrate to avoid extreme winter temperatures.
Without these extraordinary travellers,
we would never have survived our desert explorations.
Human travel has moved on.
The bicycle, forerunner of the automobile,
was a unique means of individual transportation.
But while we now rely on fast machines and savvy tech
to get around, animals have only their fins, wings,
hooves and, of course, their brains to get from A to B.
Whether it's a local trip to find food...
..or an epic journey to reach a safe place to have young...
..every traveller must work out where to go
and the most energy efficient way to get there.
The record for the longest migration goes to the Arctic tern,
flying 44,000 miles from their breeding grounds in Greenland...
..to feed down in Antarctica and then back again.
In their lifetime,
they can fly the equivalent of 60 times round the planet.
Truly mindboggling.
Of course, they're not the only long-distance migrant.
On land, caribou travel the furthest, up to 3,000 miles a year.
That's like walking from Land's End to John o' Groats five times over.
And in the ocean, the current record goes to a loggerhead turtle called
Yoshi, who was recently tracked swimming
nearly 22,000 miles in just two years.
In the endurance stakes,
these travellers are truly world leaders, but what I find even more
remarkable are the mental maps and the route planning that's involved.
What are the challenges that these animals need to overcome
and what's the brain power they need to muster to do it?
One basic requirement for being a long-haul traveller is knowing
where you need to go and, over in Wyoming,
the resident mule deer must cover a lot of ground to find enough food.
Each year, they spend up to four months on the move,
migrating between their summer home range
and their winter hideout further south,
a trek of up to 150 miles.
Mule deer are very fussy eaters
and will munch on only the most nutritious plants.
So, if they don't migrate,
they may run out of the essential nutrients they need to survive.
Until recently,
we knew very little about how they navigate around their landscape,
but, now, a long term study that's collaring and tracking females
and their young is showing that they certainly have a better
sense of direction than most humans.
I've been in these areas for multiple years, in some cases,
and I am always having a GPS with me
and I normally look at the area on a map
and, so, I should have a really good sense of where I'm going
and what's going on and I still get turned around all the time.
And deer don't.
Graduate student Rhiannon Jakopak, from the University of Wyoming,
is part of a research team tracking mule deer across the state.
She's discovered that they don't just have an uncanny
sense of direction, the timing of their migration is key.
The deer smartly stop over in areas just as high quality food
starts to grow, a strategy known as surfing the green wave.
Green wave surfing is when mule deer are moving across a landscape
at the same time that vegetation is growing in the spring.
Plants and vegetation can be really nutritious when it's first starting
to grow, but, when it's first starting to grow,
there's just not a ton of it around.
By timing their migration to coincide with the budding plants,
they ride the crest of the growth wave.
And that's surfing. They surf!
Green wave surfing might help deer work out when to migrate,
but how do they know where to migrate to begin with?
Some of the things we've been finding so far is that mule deer
seem to be learning their migrations from their mom.
Because they are really close to their moms for that first year
of life, that is a really good opportunity for them
to learn a ton of information.
So migration routes
and home ranges get passed down from mums to fawns and a 2019 study found
that deer used mental maps, handed down over multiple generations.
Without this knowledge, migrations simply can't take place
and it's not just deer who follow in their ancestors' footsteps.
Other hoofed mammals, like big horn sheep, also learn migration knowhow
from their predecessors.
But interesting new research by Rhiannon shows that some
individuals break away from these handed-down routes.
They are explorers, leaving Mum to forge their own path.
Today, Rhiannon's on the lookout for one remarkable deer called F210.
F210 is a trailblazer and just one of the coolest deer.
She's really special!
When she was one year old, she actually just kind of took off
and went on this really weird walkabout journey.
So she went 60 miles just away from where she had ever been before
and we know that she never been in this area before,
because we've had her collared since the day she was born.
Her mom didn't lead her there and we know that,
because we have her mom collared.
So she went up and over mountain ranges,
navigated through forests and crossed rivers.
But, after roaming around this unknown territory,
the call for adventure was replaced with the pull of home.
On a Monday morning, she just decided to turn around...
..and take exactly that same path back to her summer range.
And she didn't get lost.
She was able to just somehow retrace her steps entirely and so that's
really the movement that made us start to think, like, "OK, maybe
"deer do have this ability to gain a bunch of information,
"but do it, like, really, really quickly
"and after only being exposed to it just one time."
Just really got us thinking about how much
we aren't really appreciating the cognitive abilities of mule deer.
That's incredible.
It shows that these deer are constantly collecting details
about their environment and their position in it,
to establish their own new routes, different to those learned from Mum.
This spatial awareness suggests significant brain power.
So I bet you're wondering how they do it?
Well, as they move through a landscape,
landmarks and sensory details, like colours and smells,
are collected and processed as spatial memories by a key area
of the brain, the hippocampus.
When an area is revisited, any combination of these reference
points may help mule deer retrace their steps,
but it's still unclear exactly which cues they use.
We don't really know what it is that they are actually cuing
in on and remembering.
So are they remembering that, "Oh, there's a ridgeline over there,"
or are they remembering certain smells of a landscape
and how that changes?
One thing's for sure.
Mule deer are masters of mental maps - and they're not alone.
New research in 2019 has shown there's another North American
migrant that knows how to be in the right place at the right time
Like the deer, their daily challenge is to find enough food.
On land, it may be possible to perpetually graze on your journey...
..but what about in the ocean, where your food is constantly moving?
I've been studying the blue whale population off the West Coast
for about three to four years now.
They're the largest animal on Earth.
They're larger than any dinosaur that ever existed.
And yet they eat some of the tiniest animals in the ocean.
Dr Briana Abrahms is an assistant professor at the University
of Washington, where her research is revealing how these behemoths
use a smart foraging strategy to avoid going hungry.
She studies blue whales along the West Coast of America,
as they migrate from their breeding grounds in the south
to their feeding grounds in the north.
A round trip that can cover a whopping 4,000 miles.
If you think about if you were to drive 4,000 miles...
..that's going to take a lot of gas.
And whales, to fuel their migrations,
they rely on a lot of food.
These blue whales can actually eat between four and eight tonnes
of krill per day.
That's the equivalent of guzzling down about four small cars daily.
And yet these giants only eat krill,
tiny shrimp-like creatures.
Krill give them the energy they need not only to migrate,
but also to breed and nourish their calves.
But finding krill in the vast open ocean can be tricky.
Their distribution is patchy, and it's constantly changing.
This led Briana to question whether blue whales might be able
to predict where krill will be,
in a similar way to how migratory deer surfed the green wave
of plant growth on land.
Could blue whales be following a pink wave of krill along the coast
as they're migrating?
And so that's really what sparked the study.
To find out, Briana needed to know the location and times of krill
hot spots, and if the whales' migration coincided
with this glut of food.
We had ten years of satellite tagged data on blue whales,
where we could see where they were migrating.
So this is an animation of the tracking data that we used,
which was for 104 blue whales.
Then Briana matched up this tracking data with satellite maps
of where and when there were blooms of krill.
What we expected to find was that the whales...
..were hitting these hot spots
at the times that they actually peaked in each year.
So if krill peaked at lower latitudes, say, on May 1st,
in a given year and, in other years, maybe May 30th,
what we found is that, instead of actually hitting the peaks
in each given year,
they were timing their migrations to hit the long-term average.
So, in this location, on average, they would arrive around May 15th.
And we saw that they were doing that all along the coast
as they moved up.
By matching their migrations with the long-term average
of when krill are most abundant, the whales increase their chances
of being able to refuel all along the coast.
This suggests some serious brain power.
Using their memory of past foraging locations,
blue whales predict where and when there'll be a steady supply
of food, and time their migrations to match the krill wave.
Pretty remarkable,
considering their food is constantly on the move.
So they plan their trips cleverly, just like we might do.
Say you go on a fishing trip every single year and you know that,
in general, the river that you like to go to, all the fish
generally come in July, but sometimes it's early July,
sometimes it's late July.
Maybe you would plan your trip for mid-July, to kind
of hedge your bets.
And it seems like whales are doing the same thing,
and that, to us, is what indicated that they must be relying on memory,
in addition to just sensing their environment in real time.
So that was really a eureka moment.
These highly intelligent, long-lived animals
have a migration master plan,
drawing upon knowledge gained over decades to find the best krill
hot spots at the right time, year upon year.
Amazingly, blue whales are the only marine creatures that we know of
who use their memories to migrate.
This has really changed what we thought about whale migration,
that it's not just about getting from point A to point B,
but what happens in the middle is incredibly important.
And the fact that they are relying on their memory to time
their migrations helps us understand how they're making these decisions
as they navigate the ocean.
Some very clever strategies there from the whales, when it comes
to planning their next meal.
Very smart indeed.
But what about our largest land mammals?
African elephants, and water, in terms of a resource.
Well, an African elephant needs to drink 50 gallons -
that's 200 litres of water, every day just to survive.
And, given that they move around in herds of 25 or more,
that would mean that they would need a water hole something like this.
Not something they can leave to chance, just to happen across.
They need to know exactly where those water holes are.
Let's take a trip to the Maasai Mara game reserve in Kenya,
one of the best places to see elephants.
I really love my job, I really love nature.
Really love sitting down, watching the animals' behaviour.
Sophie Sadera is one of only a few female safari guides in the country.
And there's one animal traveller she's spent a lot of time with
over the years.
There are these elephants crossing the road.
Look at that tiny baby.
He's playing with that plant.
This is one of the best things,
to sit and watch, and just enjoy them.
This baby could live until it's 70 years old,
but, for now, it's heavily reliant on the herd.
An elephant group is led by the oldest female.
This is the matriarch, the one closest to us with one long tusk.
So she's the matriarch of this group.
It's her responsibility to keep the group safe,
and guide them on their migrations.
Elephants can really, really travel far,
because, actually, yeah,
I can say maybe all year round they have food,
but they travel for water.
During the dry season,
a herd can cover almost 25 miles a day to find water,
and they rely on the matriarch's spatial memory to locate it.
Researchers have found that older matriarchs with more experience
are better at seeing their family through a drought
than younger matriarchs.
When their usual water sources dry up,
they can remember how to find alternative water holes
that they visited in the past.
And the Mara's elephants offer some insight into how these routes
are passed down the generations.
If you look at that escarpment ahead of us, there is a path.
That's the elephants' path,
and they use that path to go all the way up the hills
and, down, they use the same path.
They'll go for years using the same route.
By using the same paths all the time,
younger members of the herd learn where to go in times of crisis.
When they're within a kilometre of a water source, their incredible
sense of smell takes over to guide them in.
With nearly 2,000 olfactory receptors,
their sense of smell is five times stronger than our own.
Recalling remote, life-sustaining sources of water
is critical to their survival.
But, when times are good and water is abundant,
the elephants know how to take advantage.
Perhaps the notion that an elephant never forgets
is more accurate than we realised.
Travelling from A to B is critical for migrating animals to find
the resources they need to survive and memory helps them do it.
But you don't necessarily need a big brain to have a mental map.
It turns out there's one tiny amphibian that's
a memory mastermind.
Look at this.
Superb.
This is a green and black poison dart frog - Dendrobates.
And it's exquisitely beautiful, but also highly toxic,
hence me wearing the gloves.
But it's the first amphibian that we know of, that can make
a mental map of its environment to look after its young.
What about that?
Now, these creatures live in the rainforests of South America.
A very intricate and complex environment.
This is very much a three-dimensional world,
and it's here that they, along with other poison dart frogs,
like this strawberry poison dart frog,
care for their young.
They lay their eggs in leaf litter,
but, once hatched, the tadpoles must be taken to water without delay.
And that involves a piggyback ride up to the treetops.
They need to find a hole full of water to act as a tadpole nursery.
That can be high up in the canopy.
Now, brand-new science on green and black poison dart frogs
has uncovered just how they find their way around -
up, down and in all directions in these vast forests.
This tiny little amphibian has got the mind to remember the structure
of a rainforest, a dynamic environment
which is constantly changing.
So it doesn't only form a mental map,
it has the capacity to constantly revise and update it.
Incredible!
At the moment, it's the only species we know of that can do this.
But it's likely that other poison dart frogs can do the same.
So mental maps help animals find their way from A to B,
both in their home territory and on their epic migrations.
But what if you constantly have to travel to new places to find food,
and then need to find your way home again safely?
Well, fascinating research into one ocean species is revealing some
surprisingly clever navigation strategies.
Mantis shrimp travel around the sea floor, foraging for food.
They're not shrimp, but stomatopods,
a kind of carnivorous marine crustacean.
When hunting, these little creatures pack a punch,
delivering a lightning fast strike,
as quick as a bullet leaving a gun.
Navigating underwater can be challenging.
In shallow tidal areas, the waves push and pull,
and visibility can be poor,
making it hard to keep track of where you are,
and how far you've gone.
So you'd think a small animal, with an even smaller brain,
would find it tough too.
In fact, it's quite the opposite.
They seem to have a great spatial awareness of their surroundings.
This led me to ask the question,
how are mantis shrimp navigating in their environment?
PhD student Ricky Patel, from the University of Maryland,
has been studying mantis shrimps for the past six years.
By devising a series of ingenious tests,
he started to uncover the impressive skills they use to get around.
To study them, Ricky placed food in a circular arena,
and watched how the shrimp travelled from their burrow to search for it.
So I found they make these twisty paths to the location of food.
And, much to my surprise, I found that they returned in a straight
line back to that their home once more.
This suggested mantis shrimp use a navigation technique known as
path integration, or dead reckoning.
It means they're constantly monitoring the turns they make
and the distance they travel away from a starting location
like their home.
And calculating how to return to it in a straight line
from their current position.
In fact, a similar system monitoring speed, direction and time was used
by ancient mariners to find their way back to port
after travelling at sea.
To path integrate,
mantis shrimp must have some sort of internal compass
to orientate themselves,
but they may also be using cues external to the body,
things like the sun.
This led Ricky to question what exactly they do use to navigate.
So, in the arena, I had an artificial burrow,
set into the base of the arena, so that's this dark rock.
I built a platform that could be rotated, and I placed
that directly centre in the arena.
Now, I placed food on that platform
and waited for mantis shrimp to find their way to the food.
So once they found the food on the platform,
I slowly rotated the mantis shrimp 180 degrees...
..and observed which way they went.
Cunning!
If they only used internal cues,
Ricky expected the shrimp wouldn't realise they'd been rotated,
and should walk in the opposite direction of their home.
But if they were using external signs, they'd travel directly back
to it, despite being turned.
I found that on clear days, like today,
when the sun is clearly visible,
mantis shrimp oriented correctly home.
However, on heavily overcast days,
when all spatial information was obscured...
..mantis shrimp oriented in the direction opposite of their homes.
So when it's cloudy, mantis shrimp rely on internal
self-motion cues to navigate.
But, on sunny days,
they appear to use cues outside the body, like the sun.
To check this, Ricky devised a clever twist on the test.
I would shade the arena from the sun using a board,
and then I would use a mirror to reflect the sun
on the opposite side of the arena,
to make it appear to the mantis shrimp that the sun is
on the opposite side of the sky from where it actually was.
And I found that most of the time mantis shrimp would indeed orient
in the wrong direction of their homes, after I'd mirrored the sun.
So this showed that mantis shrimp were using the sun for orientation.
That's not all.
Mantis shrimp have yet another way to avoid getting lost.
Local landmarks.
You know how the local pub signposts you're almost home?
Well, the same appears to be true for mantis shrimps,
as Ricky's latest research in 2020 found,
when he added a landmark to the research arena.
Represented today by this feather.
So in this experiment, mantis shrimp left their homes,
and, like always,
made a twisty path away.
While the mantis shrimp were doing that,
I slid the landmark to a new location in the arena.
Despite being moved, some of the time,
the shrimp still honed in on the landmark.
It seems that path integration isn't perfect,
so, to correct for this,
some shrimp also use landmarks.
Their little bit of coral signposts the way home.
So these smart stomatopods navigated a multitude of ways,
error checking their position and route as they go,
and working out which strategy is more effective at any given time.
But why would a shrimp need such a sophisticated navigation system?
Well, they may not travel far, but their lives depend
on finding their way back to the safety of their burrow.
In the natural world, path integration is a big deal,
and mantis shrimp are the only underwater animal known to use it.
Mantis shrimp are small animals with relatively simple brains.
I was really impressed, and quite surprised, by the sophistication
of their navigational authorities.
Daytime navigation is one thing, but what about at night?
When there's no sun to steer by,
how do you find your way?
Well, there's one insect
whose night-time guidance system...
..has left me suitably impressed.
The dung beetle.
A very successful group of animals.
You can find thousands of species across every continent,
apart from Antarctica,
and as their name suggests,
they either live on or in dung,
and they, or their larvae, feed upon it.
Imagine you're on the plains of Africa, and an elephant poos.
That's a lot of a very valuable resource.
Competition for that poo is intense.
So as soon as you've rolled your ball of it,
you want to get it out of the way quickly.
And the best way to do that is to roll it in a dead straight line.
Something that's quite difficult to do when you're pushing it backwards
and you can't see where you're going.
So how does a dung beetle make a quick getaway
with its precious dung ball?
To find out, we need to take a trip to the African Savannah.
The dung restaurant on the Savannah is open 24 hours a day.
There are beetles that are there during the day,
and then there are other species that are active during the night.
And that is a way to avoid competition.
It's to make sure that you can get dung.
Marie Dacke is Professor of Sensory Biology
at Lund University in Sweden,
and she's been studying dung beetles for over 20 years.
There can be thousands of beetles on a single dung pile,
and about 10% of the beetles at this pile will roll their ball away.
These are the rollers.
But there are also tunnelers,
who burrow into dung,
and dwellers, who live in it.
Yes, as you might have guessed, dung beetles are grouped
by how they use a poo pile.
But there's a fourth kind.
The stealers,
who will snatch the rollers' balls.
So once the rollers sculpt their prize...
..they'd better hightail it away.
It's the way to make sure they get their little lunch this day,
because they will eat the dung
and, by rolling straight, they get away from the dung pile,
with maximal efficiency, with every step they take.
Going in a straight line means they cover the most distance
in the shortest time - an efficient way to travel.
What's more, rolling these balls is no small feat.
Sometimes we find dung balls that are this big,
and those they are actually going to use to have their brood in.
They are pushing an object that is many, many times heavier
than themselves.
Relatively, they are the strongest animals on the planet.
Rolling their dung balls is the equivalent of us humans
pulling six double decker buses.
Since a fresh dumping of poo can happen day or night,
different dung beetle species are active at particular times.
Marie and her colleagues wanted to understand what visual cues,
such as the moon,
these tiny beetles use to orientate themselves after dark.
So they focused their studies on nocturnal,
ball-rolling dung beetles in South Africa.
And they made a remarkable discovery.
They confirmed these dung beetles do use the moon to navigate.
But there was another, even more surprising finding.
The last experiment was to have no moon at all in the sky,
and we expected them to now be fully lost.
But they were not.
They kept on orienting,
and we wanted to see if they were actually using things in the sky.
So we gave them a hat, to block everything in the sky.
And they look really, really fantastic in hats!
Dung beetles in hats!
An inspired a bit of research.
And then when they couldn't see the stars any more, they were lost.
They started rolling in circles.
We could then draw the conclusion that there was something
in the starry sky that was important for them to orient by.
On a moonless night, the most obvious landmark is the Milky Way.
If you look into the galaxy, like you do in the Southern Hemisphere,
you have a nice streak of light across the sky.
Then the southern end is brighter than the northern end.
And the theory we have is that they actually ignore the rest
of the Milky Way and concentrate on the southern part.
So, in that way, they would have one bright area to steer by.
And Marie's findings suggest that it's this gradient of light
in the Milky Way that's really important to the beetles.
We know that if you have a light streak that is totally even,
so it's the same across,
they can't orient by that.
It needs to have a gradient,
and they follow the brightest bit of it.
The nocturnal dung beetles that Marie studied are the only
animals on the planet thought to navigate using the Milky Way.
But what's really incredible is that this star compass is only one part
of these tiny travellers' navigation system.
The Milky Way is part of a bigger study when we are trying
to understand how these animals can navigate at all hours of the day,
and then how they can combine the different cues to have a very,
very safe compass to move by.
So the Milky Way is part of this system.
It's a back-up when the moon is not there, for example.
As Marie continues to learn more about their abilities,
her respect for these mini navigators grows.
We have to remember that its brain is smaller than the head
of a needle, and still they can solve so many tasks in ways
that we didn't really imagine with our massive brains.
Incredible.
But being a successful animal traveller is not
just about navigating the best path.
You also need to be smart about how you reach your destination,
making the journey in the most economical way possible.
Generally, moving uses lots of energy.
So what if you want to save your legs, wings and fins...
..to minimise the precious calories used to move around?
Well, the natural world has some savvy solutions.
Did you know that jellyfish are one of the most energy efficient animals
in the world?
Just look at their swarms - they're mesmeric, aren't they?
You know, for their size, they can travel further
using the least amount of energy than any other ocean-going animal.
And they achieve this with a dual propulsion system,
through opening and closing their bells.
Just look.
They have a ring of muscles around the outside of their bell
and, when they tighten those, the bell contracts,
expelling all of that water that's been stored inside it,
pushing the jellyfish forward.
When the jellyfish relaxes its muscles and the bell reopens
is when the genius behind its efficiency is exposed,
as this produces a second wave of water movement,
a vortex that forms under the jellyfish,
giving it another push forward.
This extra thrust is responsible for 30% of the distance
that the jellyfish travel through the water,
and they achieve it with no extra expenditure of energy.
So whilst they might look like amorphous blobs of tissue,
they are, in fact, brilliant swimmers.
When it comes to moving efficiently,
some large birds, like storks,
have a few tricks of their own.
They use their long broad wings to catch thermals,
hot air rising from the ground.
This is a smart short cut to gain height.
Once up high, they can position their wings to glide on the wind,
just like hang gliders.
No need to waste precious calories on flapping those wings.
But there's another energy efficient way to fly, too.
I'm sure many of you will have seen birds flying
in a distinctive V formation.
Well, it's all about aerodynamics.
When cranes begin their impressive migration from Europe
to Northern Africa, they fall into formation,
with birds flying just behind
and just to the side of their flock mate in front.
Those separated feathers at the tip of each bird's wing create a force
called a wing tip vortex.
Each bird, except for the leader, gets a free lift from this vortex
created by the bird in front.
Reducing effort.
And just like a cycling peloton,
pole position is the most strenuous job.
So whilst the group benefits from the leader's slipstream,
there's plenty of switches up top.
Studies estimate birds use 20 to 30% less energy when flying in a V.
Using thermals and aerodynamics,
these masters of the sky travel for days,
barely flapping their wings.
Now, that's smart efficiency.
Birds will use winds,
they'll use those columns of hot rising air, thermals,
but could there be any other physical forces
that we don't frequently think of,
that might help transport animals around our globe?
Well, it turns out that there are.
If I take this balloon, rub it against my head,
generate some static electricity,
and this small piece of plastic
to represent an organism, and do the same...
..I can make that organism fly.
But which type of creature
could travel around the world
using static electricity?
Well, brand-new science by the University of Bristol
has uncovered how one surprising animal has conquered the skies.
Would you believe...
..spiders can fly?
At first, it might seem they just float on the wind.
But these smart spiders are actually tapping
into the earth's electric fields.
There are different levels of electricity in the air,
produced naturally by thunderstorms around the planet.
Amazingly, the tiny hairs on a spider's body can sense these
and use them to get around.
Called ballooning, they'll start by tiptoeing,
sticking up their back legs into the air
and unravelling strings of web, until their spider senses
detect the electrical fields.
As their silk is negatively charged,
it repels negative charges in the air,
generating a force strong enough
to launch them skywards.
Not all spiders can balloon,
but those that can likely use both wind and electricity
sailing along on their silk lines
wherever the wind takes them.
An almost effortless way to travel.
But why would a small spider take to the skies?
Well, flying may be part of a clever strategy,
helping them to avoid competition,
start a new colony
or even find more food.
In fact, their silk superhighway is so successful,
some tiny travellers have been found
an astonishing 1,000 miles out at sea,
and up to two and a half miles high in the air.
So these airborne arachnids certainly do get around.
But whether they can control their altitude
and choose where they're landing
is something scientists are still trying to find out.
Like the spiders, sometimes it's the animals you'd least expect
that get around in the most surprising ways.
To help me explain, let's meet one of my favourites.
Stunning, isn't it?
Absolutely stunning.
This is a rhino ratsnake from Southeast Asia,
and you can see how it got its name.
It's got this extraordinary proboscis of scales sticking out
from the front of its nose, which is actually flexible.
Its green colouration betrays this snake as a type of tree snake.
It clambers up the twigs and branches into the canopy,
where it searches for its prey.
And I've got to say, it's one of the most beautiful snakes
that I've ever seen.
Fantastic.
But perhaps it's trumped by another species of tree snake -
the paradise tree snake,
which doesn't only climb trees,
it flies out of them.
To see one in action, let's head to Borneo in Southeast Asia...
..where these snakes are fearless flyers,
especially from heights like this.
Travelling in this immense jungle might at first seem tricky.
But the paradise tree snake has an ingenious solution.
It appears to almost swim through the air.
Covering up to 100 metres.
These spectacular glides may help them escape predators,
but, with no wings, how do they do it?
New research conducted in 2020 shows us that there's more to their wiggle
than meets the eye.
The researchers placed them in a study area, high off the ground,
and gave them a fake tree to aim for.
Then, by putting markers onto the snakes,
they used motion capture technology to develop a 3-D model
of snake flight...
..and create an animation.
The team found the snakes flattened their bodies
and used an undulating horizontal and vertical motion.
Essentially, it's wiggling through the air
and, as its body curves, it acts like a wing, generating lift.
This winding movement also helps the snake stay upright,
and not roll over in mid-air,
gliding and landing safely.
The exciting research being done on flying snakes
is being used to develop innovative technology.
Snake inspired robots are already in the works.
Their adaptable locomotion means they can tackle
a variety of different terrain.
So the mechanics behind how flying snakes move could be used
as a template for dynamic flying snake robots.
The wonders of nature never fail to inspire us.
But some of the most intriguing learning is coming from studying
how animals travel en masse.
When we move together, it requires a high level of coordination -
so much so, almost 100 years ago,
naturalists were so stunned when they saw flocks moving
that they believed that the birds must have been using telepathy
to communicate.
Fast forward to the present day, and we're learning that bird flocks,
along with other collectives like shoals and swarms,
are actually tapping into a group mind.
This influences how they travel,
but it's got nothing to do with any navigating or being efficient.
It's all about smart coordination.
For us humans, there's one particular species
whose collective behaviour can have a devastating impact.
These animals are a specialised type of grasshopper called a locust.
They are boom and bust animals,
and where they're booming, boy, are they booming.
The largest ever recorded swarm was in 1875,
and probably consisted of 12.5 trillion of these insects.
But what instigates the swarming behaviour?
Well, it's their density on the ground,
because these insects can eat their own body weight
a day in vegetation.
And if you've got lots of them eating that vegetation,
then, very soon, there's not much vegetation left.
And that's when things get nasty,
because their little minds turn to cannibalism.
And no locust wants to get eaten by another locust, so it starts
to move on, and then the next one moves on, and the next,
ad infinitum, until you've got a mobile swarm.
For locusts, a swarm is triggered by a massive population boom.
But other animals, like bird flocks and fish shoals,
come together by choice.
So what can they tell us about animal intelligence?
It's almost impossible for us as humans to observe these groups,
and make sense of them.
This now captivated me.
I now wanted to understand.
Dr Iain Couzin, from the Max Planck Institute in Germany,
is one of the world's leading experts in animal behaviour.
Some of his most exciting insights are coming from schooling fish.
Iain and his team studied them in special tanks,
observing their reaction to various simulations.
We project into the background any stimuli we want.
So we can have moving dots, we can have naturalistic environments.
And this allows us to understand how the animals both interact
with each other, and how they interact with the environment
through which they move.
But as Iain adds more fish to the tank,
and their numbers grow into the hundreds, even thousands,
each individual becomes increasingly difficult to monitor.
So what we do is we programme computers to see the world for us,
to track the motion of the individuals,
to calculate where their eyes are,
to reconstruct the visual fields of each individual within the group.
And so these techniques give us a completely new insight
into how they sense, how they communicate
and how collective intelligence has evolved.
Each individual is interacting with his neighbour,
who interact with their neighbours,
and, together
these social interactions can fuse their brains together
to create a sort of higher level intelligence.
And this actually allows the groups themselves to have an awareness
of the environment that is not present at the individual level.
This means there doesn't need to be a global orchestrating
leader within these groups.
Each individual follows relatively simple local rules.
They will avoid colliding with each other.
They'll be attracted towards each other, and they will tend to move
in the direction of the neighbours around them,
and those simple rules alone,
if all of the individuals follow them, it's sufficient to explain
these large swirling flocks that we see.
Now that we know how individuals in a group respond, the question
is why do they form such large groups to begin with?
One of the main reasons is about information.
So each individual has a local sphere where it can detect what's
going on in its environment, and that's inherently limited.
However, if each individual pays attention to what's
going on within that local environment,
but also pays attention to the others around it,
and each of them is paying attention
to their own part of the environment,
and if information can flow quickly across the group...
..this effectively means, if I'm a fish at one side of the school,
I can feel what's going on at the other side.
This is all being integrated into the sort of collective mind.
So what Iain is saying is that, by one fish reacting to a predator
and by moving away from it, the fish nearby rapidly respond too,
and their behaviour is copied by the fish around them.
And, in this way, the shoal responds collectively.
There's no leader, but they act together through a collective mind.
That's a very strange way of thinking.
It's a different type of intelligence.
By coming together, these animals boost their brainpower,
forming a more intelligent whole.
And, as it turns out, the mathematical rules
behind collective behaviour in animals may be applied
to our lives too.
Using the same types of technologies, we can also
study how people move and behave within crowds.
And this is very important to improve crowd safety,
because we're not necessarily aware, when we're moving through a crowd,
when there are dangerous conditions emerging.
To stop density building up to dangerous levels can help the flow
of people through crowded environments.
So animal collectives may help keep us safer.
But there's more.
The most exciting part of Iain's work is at the cellular level.
The principles that underlie swarm formation in the animal world
also inform us at how cells form swarms.
So when we look at the movement and the invasion of cancer cells
in the body, we're realising now that almost all tumours actually
invade as a collective, whether it's a raft of cells
going through the bloodstream, or some tendrils of cells spreading
out from a brain tumour.
And so we're realising that collective behaviour
is the fundamental process that we need to understand,
to try to divert them, to try to prevent the tumours from being able
to invade tissue, prevent them from being able to spread
throughout the body.
Now that's an incredible thought.
Understanding how these collectives move...
..could help us tackle cancer more effectively.
Through developing a better understanding of how animals move
and travel, we're not only learning more about their intelligence,
we're learning how to find more intelligent solutions to help
us humans, too.
We are now beginning to realise just how smart nature's travellers are -
from their impressive spatial memory...
..to navigating using the sun and stars.
Even making their trips in the most efficient ways possible.
And, throughout this series, what I've discovered
about the complexity of animal minds,
how they communicate, build, con and cooperate,
has completely transformed what I thought I knew
about animal intelligence.
The brains of the natural world are far brighter,
more sophisticated and flexible than I could have ever imagined.