Original subtitles

Did you know,

dolphins can look inside our bodies?

Snakes have thermal imaging.

Ants can predict earthquakes

and platypus can sense electrical pulses, like a shark can.

We enjoy the rich colors,

sounds and smells of the natural world,

but it seems there is a lot we miss out on.

(playful music)

The five senses, sight, smell, hearing,

taste and touch have been taken to extremes

across the animal kingdom.

And some have powers we can only dream of.

To accommodate these superpowers,

animals have some of the weirdest features

and quirks of behavior,

revealing to them the world we miss.

(playful, magical music)

(wind blowing)

We live on an incredible planet.

(waves crashing)

(gentle music)

The endless colors,

(gentle music)

smells,

(chainsaw buzzing)

sounds,

(African drumming)

and textures of nature.

We lap them up with our key senses.

(light music)

These basic senses are common in the animal kingdom.

(light music)

Some senses, like vision, we are pretty fortunate with

and can hold our own among most animals.

(monkey squawks)

(light music)

With others, like our sense of smell,

the animals leave us in the dust.

But we can only perceive what we can perceive.

(light music)

There is a world beyond our senses we can scarcely imagine.

(light music)

We all know our sense of smell

is limited compared to animals,

especially our canine companions.

(suspenseful music)

Some dogs, like bloodhounds, can pick up scent trails

two weeks after they were laid

and follow them for a hundred kilometers or more.

(dog barks)

But their skills are not unique.

Brown bears have a better sense of smell than a bloodhound.

They're said to be able to detect food

from 30 kilometers away.

(playful music)

And polar bears can sniff out seals

that are under thick ice.

(playful music)

The sensory area to pick up and decipher smells

is 100 times bigger in a bear than it is in us.

(playful music)

Oh, I think polar bear is coming.

(playful music)

Many very diverse animals

have this extraordinary gift.

(light music)

Birds are visual creatures without a strong sense of smell.

But the turkey vulture breaks the mold.

The olfactory part of its brain is four times bigger

than even close cousin, the black vulture.

Soaring on thermals, they pick up the tiniest whiff

and can find food a kilometer and a half away.

The silk moth family are even more impressive.

Though not using their noses,

when they are ready to breed,

female moths waft pheromones, insect perfume to lure males.

The males have much larger antenna than the females.

They look like feathers, but they are scent catchers.

It only takes one molecule of scent to alert the boys.

They can pick up the traces of a potential mate

from more than 11 kilometers away.

(light music)

(ominous music)

Sharks could be called the bloodhounds of the sea.

It's thought a shark can pick out

a single drop of blood in 10 billion drops of water.

And can locate food from hundreds of meters away.

(ominous music)

But according to science,

the best sniffer is something different.

Scientists analyzed the genes in a wide variety of animals

and found elephants came out on top

with 2000 genes devoted to their sense of smell.

This is twice as many as a bloodhound

and five times more than us.

They can detect and follow the scent of water

from 20 kilometers away,

a life saving skill on the baking plains.

With such incredible abilities,

it's hardly surprising they have the biggest

and weirdest noses going.

(playful music)

(elephant honks)

(playful music)

The colossal pachyderm proboscis

does a lot more than detect smells.

(playful music)

It can lift many liters of water.

(exciting, playful music)

Pick up tiny blades of grass.

(exciting, playful music)

Or tear down trees.

(exciting, playful music)

It's a tool like a fifth leg and hand all in one.

(exciting, playful music)

On top of that, it's a trumpet.

(elephant trumpets)

These many uses are thanks to some 40,000 muscles

that powerfully control every move.

(playful music)

And of course, it's a tool for breathing.

(cow moos)

Strangely, after studying the number

of scent-related genes in different species,

Scientists concluded that cows and mice

both have many more genes

devoted to smelling than bloodhounds.

With this way of measuring,

elephants came first, followed by rats.

(playful music)

The sense of smell in those rodents is so well developed

that they can even be trained to sniff out cancer

and help to locate undetonated landmines.

(playful music)

Rats have another peculiarity among mammals,

they have binocular sniffing.

(rats chittering)

An incredible skill, so far,

only recognized in them and moles.

They can detect which nostril receives the stronger scent,

helping them to more accurately follow the trail.

(playful music)

Noses are one of the most prominent features of the face.

(playful music)

And their variety is weird,

(suspenseful, playful music)

and wonderful.

(playful music)

There are some seriously strange noses out there.

Like the proboscis monkeys of Borneo.

(monkeys chattering)

The males have hand-sized honkers

to help amplify their calls.

(monkeys chattering)

Tapirs have mini trunks to detect danger.

(playful music)

And help them pull high-growing leaves into their mouth.

(sniffing)

(playful music)

For many animals, nostrils can help filter out dust.

And in a few antelope, the function has been enhanced.

Both saiga And dik-dik have big ones.

The large air chambers help to control

the temperature of the air they breathe.

It's air conditioning.

(light music)

Even more advanced in camels, who use their large noses

to absorb moisture from the air before they breathe it out,

conserving every tiny drop.

Pigs are famous for their sensitive snouts too.

(playful music)

And their noses are unique,

(playful music)

with a tough cartilage disc at the end that they can angle.

(playful music)

It is a built-in shovel for rummaging and digging for food.

This, combined with their acute sense of smell,

is what them such renowned trufflers.

(playful music)

The key to this skill

isn't just their sense of smell, but sex.

Truffles contain a sexy hormone

that male pigs secrete in their saliva

and that the girls find hard to resist.

So if you want to uncover a truffle,

get yourself a female pig.

Though, be careful to grab it,

before she makes a pig of herself.

(water trickling)

(men speaking foreign language)

Our noses are nothing to be sniffed at

but other animals could rightly look

down their noses on ours.

But as you'll see, our vision is an eyeopener.

(light music)

Most primates have average eyesight.

But ours is exceptional.

We have three types of color-detecting cones in our eyes,

giving us a broader spectrum of colors

than most other mammals.

(water trickling)

We are not leaders in the field.

Some kinds of shrimp have 15 kinds of cones,

rather putting ours to shame.

But our vision is better than most.

(water splashes)

Most mammals use their eyes

as part of their arsenal of senses.

(water splashing)

Only a few, like bats, river dolphins and moles,

creatures who live in dark conditions

have tiny eyes and poor vision.

(light music)

Most mammals see a bit of color

but usually have fewer cones than us,

so don't see as many colors.

(light music)

It's thought that mammal ancestors were mostly nocturnal,

perhaps so they could hide from dinosaurs in the early days.

Mammal eyes have sacrificed sharpness and color

that are typical of day-active birds and reptiles

in favor of eyes that are light sensitive.

Humans are the exception.

(playful music)

We are more dependent on vision than any other mammal

and have better color perception than most.

(playful music)

Our vision isn't perfect.

We have 200,000 receptors

for every square millimeter of our eyes,

which gives us the sharpness and clarity of our vision.

Buzzards have 1 million,

so we can only imagine the incredible detail they perceive.

(bird squawks)

(light music)

But even with our quite good vision,

we are only perceiving a tiny part of the light spectrum.

There are lots of colors we can't see

and a weird and wonderful array of animals that can.

Ultraviolet is the part of light that we try to block out

with our sunglasses and sun cream to protect our skin.

The lenses in our eyes naturally block it out.

We can't see it, but many other species can.

In fact, science keeps revealing a growing list of animals

that can perceive ultraviolet, including bats,

a range of marsupials, hedgehogs, even cats and dogs.

(suspenseful music)

Whether most see and use

this part of the color spectrum is unknown,

but there are many species that actively do.

(playful, suspenseful music)

Rodents for example, like rats and mice,

can see each other's urine, glowing ultraviolet,

helping them to find each other.

(playful music)

And birds of prey like kestrels,

can also see mice urine to help them locate their dinner.

(suspenseful music)

(bird squawking)

We love the color of flowers,

their dazzling array of hues.

But we can only see the spectrum from red to violet.

Many flowers absorb or reflect ultraviolet light

to create dramatic patterns that are invisible to us.

And it's possible they use these specifically

to attract animal eyes sensitive to the colors,

such as bees.

(gentle fluttering)

Hummingbirds too, are sensitive to these floral flags.

(gentle fluttering)

But the winners are butterflies.

(playful, upbeat music)

They are believed to see a wider range

of colors than any other species,

with 15 different types of receptors.

(playful music)

They use eye-like markings on their wings

to look like predators faces to scare off attackers.

(playful music)

And they use color to attract and assess potential mates.

The vibrancy of the colors helping them to identify

the healthiest possible partner.

(buzzing)

(wind blowing)

Unlike our lenses that block UV, most mammals' don't.

So they see a little more of the spectrum than we do.

But to be especially sensitive to it is unusual.

Researchers were recently surprised to discover

that many marsupials and monotremes, like platypus

and echidnas glow under UV.

No one is sure why,

but it might be an aid to their nocturnal lifestyles,

helping them find each other in the dark.

(crickets)

Amazingly, reindeer can adapt their color-viewing

to match the seasons.

(reindeer grunting)

They shift their vision towards ultraviolet.

During the long dark months of the arctic winter,

the deer can use the extra light rays

to help them locate lichens,

which faintly reflect the UV light.

And both the urine and the bodies of polar bears

and wolves might stand out more against the snow

to the reindeer's sensitive eyes, helping to keep them safe.

(wind howling)

Many animals depend on night vision.

And rather than color-sensing cones we have favored,

they have more rods, enhancing any trace of light.

(playful music)

The most skilled specialists

have inspired road safety design.

So-called cats eyes in the road are bits of glass

that reflect back light in the same way cat's eyes do.

(playful music)

(car horn beeps)

Many species have eyes that glow in torchlight.

Known as eye shine,

the glow is because most nocturnal animals

have a shiny layer in the back of their eyes

called the tapetum lucidum, which is like a mini mirror.

It reflects light back.

The retina is the part of the eye that sees the world.

(serene music)

The dim light enters the eye

and passes through the retina in us.

But in nocturnal animals, it is reflected

and passes through again,

increasing the light the eye has to work with.

(serene music)

The enhanced image is like our night vision technology.

(serene music)

We and the rest of mammal kind

are also restricted by the number of eyes, a pair a piece.

Spiders famously have eight eyes.

Their vision isn't as good as ours,

but they have broken down the tasks

between the different pairs.

In jumping spiders, it's the big pair

at the front that sees best.

They capture the most detail,

but the other three pairs

are more sensitive to movement,

spotting predators or prey.

(playful music)

And giving the odd-eyed hopper's amazing depth perception.

(playful music)

Scallops and clams are on the ball, eye-wise.

They can have hundreds of tiny eyes

spread along the gap between shells.

Their vision is poor.

They do see some color, but not much detail.

But there are so many eyes that they can pick up

the movement of approaching predators,

just in time to clam up.

(playful music)

And dragonflies have 360 degree vision.

Thanks, not to one pair of lenses,

but 28,000 pairs of lenses.

Eagle eyes enable their lightning-fast reactions

and spectacular coordination.

(playful music)

And a few more oddballs among eyeballs.

(ominous music)

Ostrich's eyes are bigger than their brains.

They have the biggest eyes of any living land creature.

(suspenseful music)

Their perceptive peepers, combined with their height,

make them expert at spotting approaching danger.

And for that reason, antelope and other animals

like hanging out near the bird-brained watch towers.

(ominous music)

Perhaps the weirdest eyes you could imagine

belong to the chameleon.

(playful music)

Little pin pricks on the end of highly mobile stalks.

(suspenseful music)

They can move each eye independently,

enough to make you go cross-eyed just thinking about it.

(suspenseful music)

Amazingly, they can enjoy monocular vision from each eye

scanning the environment all around them

and interpreting each view separately.

But then when they spot prey,

both eyes swing forwards giving binocular vision,

the perfect depth perception.

(gentle music)

We enjoy the visuals of the world,

(gentle music)

but life's rich soundtrack can be just as exciting.

(thunder crashes)

(orchestral music)

Listening to an orchestra, the air is alive with sound.

(orchestral music)

A rich cascade of notes,

but we can only hear a fraction of the world's sounds.

(exciting music)

Many sounds are above or below our hearing range.

And our range gets narrower as we get older.

(orchestral music)

Some animals not only hear,

but harness sound in ways

that seem fit only for superheroes.

(light music)

We know ultrasound, the very high pitched sound waves

we can fire into our bodies to look inside them.

It seems like space-age technology,

But animals harnessed this power millions of years ago.

(church bell tolls)

Bats are creatures of the night.

Their eyes are tiny and weak.

There's no point investing in eyes for a life in the dark.

Their world is one of acoustics.

(church bell tolls)

Most of the sounds bats make are too high pitched

for our ears to pick up.

It's only when the sounds are slowed down

that they reach a frequency we can hear,

allowing us to listen in on their world.

(high-pitched squeaking)

As the bats fly, they make their high-pitched squeaks

and their huge sensitive ears

listen for the returning echoes of their calls.

This helps them map out the landscape

and navigate through obstacles.

(high-pitched squeaking)

And when the sound hits other animals, (thunder crashes)

like flying insects, it can help them to target their prey.

Incredibly some insects have learned

to use their weapon against them.

(light music)

Some crickets emit frequencies

that cancel out the bat sounds.

(light music)

And the wings of moths are stacked

with little scales that can absorb sounds,

softening the echoes.

(light music)

Dolphins, deploy a very similar tactic.

In their murky, churning, underwater world,

vision is not very reliable.

They produce high pitch clicks and whistles,

and again harvest the echoes.

(dolphins clicking)

They can make out the sea bed and scan for prey.

(dolphins clicking)

They can even fire pulses of sound

into the silty sea floor to detect hiding creatures.

(playful music)

It's believed that just like our medical ultrasound,

dolphins can look into each other's bodies.

(playful music)

They can check one another's health

and even look at unborn babies.

(playful music)

They can do the same to us, looking inside our bodies.

(playful music)

This one knows the lady has something hidden in her wetsuit.

It's detected the different density of the camera,

based purely on the echoes of its clicks.

While dolphins and bats

have harnessed the power of ultrasound,

sound waves too high for our ears to hear,

others go to the opposite extreme.

(waves splashing)

Whales, alligators,

even giraffes, use infra-sound,

(whale grunting)

sounds that are so deep we can only hear them

if we speed them up.

(water splashing)

The champions of this super sound wave

might be elephants again.

The very deep sounds can rumble through the earth

or through water over very long distances.

We can hear some elephant rumbles,

but others are too deep.

They just vibrate through the earth.

Incredibly, they don't just use their ears

for long distance chat, they feel their way.

Lying their trunks on the ground,

and using the rubbery and highly sensitive pads

on their feet, they can feel the vibrations

of other Ellie's rumbling as much as 15 kilometers away.

(low rumbling)

From these faint signals,

it's believed the big-brained behemoths

can triangulate where each other are,

check in on who's about, proclaim territories,

check out the dating scene,

and warn of approaching danger.

(low rumbling)

All without lifting a foot.

(water splashing)

(low bellow)

Like us, elephants enjoy caressing.

(light music)

Touch is another of the weird and wonderful senses we enjoy.

This is perhaps the first, most ancient of the senses.

Pretty much all organisms have a sense of touch.

It helps them to avoid surfaces

that are too hot, too cold, or too sharp.

(playful music)

They can sense pressure and pain,

and so help organisms to avoid danger.

(playful music)

It's how spiders know when prey has landed in their webs.

They feel the vibrations in the strands

of silk with the tiny hairs on their legs.

(light music)

(bird chirps)

Though nerve cells cover our bodies

and all over the bodies of most organisms,

detecting pain, temperature, texture, and pressure,

some animals have senses that are much more finely tuned.

(light music)

Whiskers are an animal's feelers.

(light music)

While all are embedded in nerve endings,

some are more sensitive than others.

(light music)

Manatees are covered in coarse hairs,

especially around their muzzles.

And these can detect changes in water temperature

and pressure, helping them to navigate tides

and maintain their body temperature.

It's thought pressure changes help them to detect

objects ahead of them so they can avoid a collision.

(ominous music)

This super sense is essential underwater

and several species make the most of it.

Crocodiles and alligators have thousands of little pores

on their snouts that can detect vibration.

And these can help guide them to the movements of prey.

(water splashes)

(ominous music)

But the feel fanatics, the champions of touch, are seals.

(playful music)

Their whiskers have far more nerve receptors

than any other animal.

(playful music)

In the murky seas, they use the fan of hairs like a hand

to feel their environment.

They are so sensitive that they can pick up

pressure changes caused by the swishing of a fish's tail

nearly 200 meters away, guiding them to their food.

(playful music)

Taste is another vital sense.

(playful music)

We use it to enjoy our food.

(playful music)

But for animals it can be essential,

allowing them to taste when food has gone off.

(playful music)

For us and most other animals,

it's all about taste buds on the tongue.

We can only taste what we put in our mouths.

(playful music slows to a stop)

We have about 10,000 taste buds.

But catfish have 175,000

and they are not confined to their mouths,

they are all over their bodies.

(ominous music)

Catfish can literally taste their surroundings,

ideal for trying to find food in murky water.

(light music)

For all five of these senses,

we have a taste of what it's like.

(playful music)

But some oddball animals have superpowers

we can barely imagine.

Infrared is something our thermal imaging cameras can reveal

by reading the heat signature of animals.

Warm blooded animals appearing warmer in color

against the cool landscape.

Incredibly, some snakes can do the same

using only holes on their heads.

(ominous music)

Boas, pit vipers and pythons,

like this Burmese Python, have pit organs

the series of holes in their snouts.

(ominous music)

They read thermal radiation,

the waves of heat coming from anything warm.

(ominous music)

They can use it to sense ground temperature

and so find places to warm up or cool down.

And it helps them hunt.

(slow, ominous music)

Even in complete darkness,

they can gather enough information from the pits

to build a mental image of the location of their prey.

And accurately plan their strike. (snake hisses)

(dramatic music)

Senses are innate,

they need a bit of fine tuning as species grow.

(bird chirping)

But these amazing gifts are born into us.

(bird chirping)

And can lead to the seemingly impossible.

One of the most extraordinary

occurs when young birds leave the nest.

They are born to migrate.

(playful music)

Some will travel halfway around the world,

but somehow they will do so alone.

(birds chirping)

They do not learn by following their parents.

They just seem to know.

A super sense, deep within, will tell them when to fly,

how far and in what direction to get them

to a safe place to spend the winter.

(dramatic music)

Scientists have caught and moved birds

to different locations,

places that they have never been before.

And before release, tried many measures,

such as keeping them in darkness

and using magnets to block the Earth's magnet field

to try and eliminate different cues.

But the birds somehow always find their way home.

There's evidence that from a young age,

birds watch and learn to track the movement

of the sun and the stars,

building a mental compass.

(light music)

(birds chirping)

They also remember landmarks,

(light music)

even following roads.

(light music)

(birds squealing)

And there is good evidence

they can build a mental map with their sense of smell.

(light music)

Sniffing the ocean to one side,

a forest to the other and so on.

Key features that can help guide them.

(light music)

(birds chirping)

Birds' ears, eyes and beaks

all have special connections to their brains.

And there can be tiny traces of iron in their ears

and magnate, a magnetic rock, in their beaks.

(light music)

These mean birds are born

with the ability to read the Earth's magnetic field.

It's strength growing stronger

away from the equator and toward the poles.

(fluttering)

None of these traits can be solely responsible

for navigating such vast journeys.

(dramatic piano music)

And they can't explain how young birds

seem to know on their own to migrate and where to go.

(dramatic piano music)

Birds clearly have own built-in GPS system,

but how this superpower is used continues to baffle us.

(birds cawing)

The furthest reaches of our super senses are mind blowing.

(water bubbling)

Many animals also have shocking skills

when it comes to sensing electricity.

All life gives off faint electrical charges,

barely perceptible energy generated by functioning cells.

And a few animals are fine tuned to detect it.

Most famously sharks.

Their snouts are covered in pores

that contain Lorenzini jelly,

perhaps nature's most powerful conductors of electricity.

With this power, they can locate

the pulsing muscles in potential prey.

(playful music)

It can run, but it can't hide.

(birds chirping)

There are other ways to monitor these little charges too.

(birds chirping)

Flowers can have a very slight negative charge.

(buzzing)

The hairy legs of bumblebees

seem to be able to pick this up.

As the bees fly, the tiny hairs pick up static,

a positive charge and the polar opposite of the plants,

enough to guide them to a flower.

(light music)

Bees also use the Earth's magnetic field,

perhaps because of tiny traces

of magnetite in their bodies to navigate,

an inbuilt creepy crawly magnet.

(light, inspiring music)

Red ants have the skill too, and may even use

the electromagnetism to detect earthquakes.

(light music)

They have been seen to batten down the hatches,

preparing their mounds way ahead of the quake.

(playful music)

(waves crashing)

One animal seems to combine

many of these remarkable traits

in one of the weirdest forms of all.

(water bubbling)

The unmistakable profile of a hammerhead shark.

(ominous music)

Its broad mallet of a head might be useful

for pinning down prey like stingrays,

but it also aids its senses.

(ominous music)

It creates a huge surface for electron receptors

that can help it navigate

by reading the Earth's magnetic field.

(ominous music)

And it spreads its eyes and nostrils far apart,

giving binocular sight and smell.

(ominous music)

It might have better directional senses than other animals

thanks to being something of an oddball.

(ominous music)

Super senses and the weird and wonderful animals

that have them enrich the planet.

But our noise pollution,

(gulls squawking)

light pollution,

(light music)

and chemical pollution

are dumbing our senses and making it harder

for animals to use their skills.

(dramatic music)

Let's encourage change

(birds squawking)

before the only place for superpowers is comic strips.

(light music)

(monkeys chattering)

(light music)