(light music) (bugs trilling)
(tiger grumbling)
(crickets chirping)
(wind whistling)
Anyone fascinated by the natural world
has probably wondered why some animals
have such strange looking sense organs.
The elephant with its huge ears,
the antennae of a butterfly,
which up close look like feathers,
the snake with its split tongue.
And what about less obvious enhancements,
like the sensory cells on a crocodile's skin?
Surely these evolutionary traits aren't just for decoration.
In fact, the size, shape and location
of these animal sense organs is all for a purpose,
and just like us, animals rely on their senses
to communicate with each other, find their way around,
stay safe, and most importantly, to find food.
When you see how superior some animal senses
are compared to those of humans,
you might wonder how we ever managed to stay
on top of the food chain.
Animal super senses, you won't believe what's possible.
(light dramatic music) (bugs chirping)
On this episode of "Animal Super Senses"
we examine how things taste
and how vital scent is from the animal perspective.
You may think that there are no gourmets
in the natural world, after all,
animals eat for survival, not for enjoyment as we know it.
So surely only humans are capable
of differentiating one taste from another.
Actually it's much more complicated
and interesting than that.
In the animal world the distinction between taste
and scent tends to be more blurred.
For example, for terrestrial animals,
those that walk on land,
taste is all about detecting chemicals called tastens
that stimulate the sensory cells in a taste bud.
But their sense of smell will also detect the scent
of odorants carried through the air.
In mammals, taste receptor cells are scattered
all over the tongue.
In other creatures, they can be located
in some fairly odd places.
How taste and smell receptors work under water,
well, it's a whole other world.
(light dramatic music) (wind whistling)
(birds chirping)
Let's begin our journey as it were, from the ground up,
with a look at snakes and their taste for a good bite.
This slithery character is a rattlesnake.
Such as can be found across the Americas,
from Southern Alberta to Argentina,
in a variety of habitats.
(snake rattling)
The one thing that all rattlesnakes have in common
with other snake breeds is their uniquely good taste.
They use those famous forked tongues to gather particles
from the air and identify them
on a special membrane called Jacobson's organ.
Put more simply, they flick their tongues
to taste the scents around them.
So next time you see a snake sticking its tongue out at you,
remember, it's not trying to sting you from afar,
but searching for prey.
(light dramatic music)
Tasting their next meal before they eat it,
you could even say, they have an exceptional sense
of smell to begin with, but their Jacobson's organ
adds a whole other dimension.
The Jacobson's olfactory sense organ was actually
discovered by Ludwig Jacobson, who it's named after.
(snake hissing) (light dramatic music)
(mouse chittering)
The organ that now bears Jacobson's name is located
on the roof of the mouth in many reptiles and mammals.
Mammals would include us, surely.
Well, apparently humans are an exception.
(birds chirping) (bugs trilling)
(light music)
Now, unlike snakes and lizards,
mammals that come with Jacobson's organ
as standard equipment tend not to have long forked tones
that they can without a will to sample the air.
(mouth crunching)
So, instead, they do something else.
It's called flehmening.
Domestic cats do it, for instance.
And so does this character, the taper.
Looking a bit like a pig with a trunk,
tapers actually belong to the same family
as the horse and the rhinoceros.
They can be found in the jungle and forest regions
of Central and South America, and in Southeast Asia.
Tapers' eyesight isn't great, but they have
a heightened sense of smell, plus the secret sensor
that is the Jacobson's organ.
When they curl their upper lip
and look like they're sneering,
the same way you've seen some domestic cats do,
they're actually exposing the Jacobson's organ
so they can taste exactly what's in the air.
The taper is an herbivore.
That long snout with a modified lip comes
in handy for tearing food off branches, for example.
What the leaves tastes like to the taper,
perhaps, we'll never know,
but we do know how it finds its sustenance.
(upbeat music) (waves crashing)
Below the waterline, whether that's a pond, river,
or the ocean waves, taste and scent is a whole other matter.
One underwater animal who is guided by scent
is this sinister and slippery looking character.
The moray eel.
Even though there are hundreds of species of moray,
and they range in size from 25 centimeters to four meters,
the menacing appearance of a moray eel with its mouth
constantly agape is unmistakable.
Morays are carnivores who feed on fish and invertebrates.
They're also founded oceans temperate and tropical,
though they thrive in the greatest number
around warm coral reefs, notably in Hawaii.
They have something of a reputation for aggression
and what might even be called a bad temper,
but actually, when they sense humans approaching
they usually flee our hide in crevices.
Mind you, it's usually from the same crevices,
nooks and crannies that morays launch their fatal attacks.
When they do they are led, as it were, by the nose.
Moray eels' eyesight is poor and they rely
on their tube-shaped nostrils to scent and seek out prey.
Fascinatingly, one of the moray eels' preferred victims,
the octopus, has evolved a chemical in its jet black ink,
which is capable of neutralizing
the moray eels' powerful sense of smell.
On its travels, the moray eel will quite possibly
also come across the goatfish.
These are also found in shallow waters,
particularly in warm or tropical climes,
skimming along coral reefs over mud or sand.
They have twin barbells hanging underneath their chin
which must be where they got their name.
As they look like goats' whiskers,
or if you're feeling particularly imaginative,
like a droopy hipster's beard.
Some goatfish are nocturnal and have a chameleon-like
ability to change their color.
But what they all seem to have in common
is their hearty appetite.
Goatfish spend their entire lives looking for food.
How they find it is by utilizing those barbells.
Goatfish, or what is known as bottom feeders,
skimming along looking for their next meal
in the sand below.
Those barbells are spotted but taste buds that will zone
in on anything that's good enough to eat.
For example, shrimp, crabs, clams, and clam worms.
Goatfish are guided by their sense of taste
and smell to their next meal,
and the one after that, and the one after that.
But there are some underwater animals who deploy
this super sense, not so much in the hunt for food,
but as a sophisticated homing device.
It's called needle homing by the experts.
Now homing is something we associate with animals
above the waterline, most commonly cats and pigeons,
but it is now known that several marine animals,
such as elephant seals, salmon and sea turtles,
may travel considerable distances of ocean
before they return as adults to reproduce
in the same natal area they were spawned.
(light music) (water bubbling)
Sea turtles outlived the dinosaurs,
yet today five of seven species are
on the endangered species list.
They also take a long time to reach sexual maturity,
a decade or more, so observing them and drawing conclusions
is a time-consuming and painstaking business.
(light music) (waves crashing)
Sea turtles spend their whole lives at sea,
except when adult females come ashore to lay eggs
in the territory where they were born.
The question is, how do they do it?
It's thought that sea turtles find their birth beach
by homing in on the chemical signature unique
to where they were born, essentially tasting their way home.
With these amazing abilities,
that's what we call a real super sense.
(upbeat music) (waves crashing)
(water bubbling)
(birds squawking)
The case of the salmon's homing instinct is another baffler.
(water rushing)
Most salmon are born in fresh water.
They migrate to the ocean where they will spend four to
five years eating and growing.
At maturity, they return to breed and lay eggs
in the freshwater streams they were born in.
(water trickling)
When they return to fresh water to breed
it was assumed that salmon used the scent
of the water to find their home stream,
and certainly, the salmon's olfactory sense is astonishing.
But now scientists are starting to question
if salmon also navigate using the Earth's magnetic field.
Either way, those are some super senses the salmon deploys.
(light music) (birds chirping)
(crickets chirping)
Another way, in which scent is critical for animals,
is when it comes to marking their territory.
Leaving a scent stamp on their territory,
most animals don't waste a lot of time being subtle.
The lion urinates on a tree to mark the boundaries
of his kingdom and advise any other lions
who come along that this tree is taken.
The hippopotamus, however, scatters its feces
to let intruders know who's in charge around here.
This is called dung showering by those who study hippos,
and something else by anyone who happens to be around.
So far, the animals we've discussed who mark their territory
do so unfairly standard ways, even if, like the hippo,
they tend towards the alarming.
But nature's endless adaptations never fail to amaze.
(light dramatic music)
Take the Thomson's gazelle,
which is typically found on the African Savannah.
The male Thomson has a particularly odd way
of marking its territory.
When it's mating season, they establish breeding grounds
by leaving their scent in an unusual manner.
Secreting a smelly substance from a gland below its eye,
the Thomson's gazelle sticks the stuff on grass stems
to ward off male interlopers and attract females.
(light dramatic music)
(grass rustling) (bugs chirping)
(upbeat music) (birds chirping)
A long away from the African plains and the woodlands
of Queensland in South Australia
you'll find one of those animals that we humans
like to think of as cute.
The koala, of course, is not to be confused
with bears of any kind.
For, of course, this is a marsupial
whose closest relative is the wombat.
This photogenic Aussie sleeps up to 20 hours a day
and has one of the lowest brain to body ratios
of any marsupial.
If you come across one in the wild urinating on a tree,
you would see it marking its territory.
Particularly, if it was a male like this cheeky fellow.
But the male koala scents his territory in other ways, too.
You can distinguish the fully developed adult male koala
by its quite visible chest cavity
in the middle of its chest.
It's actually a scent gland.
And it's the scent gland on his chest
that the adult male koala uses to mark his territory.
Rubbing its chest against branches and twigs,
usually at the bottom of a tree,
produces an unusual reaction.
This interesting activity triggers a particular sensation
within the male koala, or buck.
This sensation is accompanied by the secreting
of a scented fluid that is exceptionally attractive
to female koalas.
When this is done, not only has the male koala marked
his territory as a breeding ground,
he's probably already in the mood for love.
(crickets chirping) (light music)
The bolas spider, also known as the angling spider,
uses sex pheromones to ensnare its prey.
It's known as aggressive mimicry,
where a predator copies something from their prey
in order to confuse or entice it.
The bolas spider admits a pheromone indistinguishable
from the female moth and lures male moths to their doom.
It's a key weapon and the bolas spider's arsenal
as this is one spider that doesn't catch
its victims in the usual web.
Instead they hunt using a sticky capture blob
at the end of a line, which they swing
at male moths drenched, of course, in false scent.
(light music) (crickets chirping)
(water rushing) (birds chirping)
(light music)
Now for the final segments of the program
to look at some genuine super sense sniffers.
Let's begin with those lords of the forest, the wolf.
A wolf's sense of smell is estimated
to be 100 times stronger than humans.
They use it to locate other members of the pack,
their enemies, and of course, their prey.
Scent will tell them if other wolves have been in the area,
how many there were, male or female, and how recently.
The wolf has several specialized scent glands on its body,
including its back and about three inches from its tail.
The scent it produces from these glands is as distinctive
as fingerprints are to a forensic crime lab.
Each and every wolf's is different.
(suspenseful music)
Wolves mark boundaries and trails using the smell
from these highly individual scent glands.
You might say their own personal calling cards.
These trails and boundaries, or scent stations,
can be up to 100 meters apart.
Mankind has benefited from observing this behavior.
As dogs have a scent ability close to that of wolves,
training techniques have evolved
which imitate the wolf in the wild.
You can see this in search and rescue dogs,
as well as police and drug detection.
(wolves howling)
(light music) (birds chirping)
Second of these super sense sniffers,
one of the greatest noses on earth
belongs to the mighty bear.
For some reason it's gotten about
that bears have poor eyesight.
That's simply not true,
but they rely on scent and smell even more.
Their acute sense of smell helps them to track down food.
For example, bears can detect a dead animal
from 35 kilometers away.
Smell helps bears to find mates, keep a track on rival bears
and mothers to keep track of their cubs.
Bears communicate with one another using scent.
By leaving scent on trees and vegetation,
they broadcast a message to other bears
that may be in the neighborhood.
Even though a bear's brain is about the third
of the size of a human's, the area of its brain,
which manages smell, is at least five
times larger than ours.
But it's not all that cerebral, far from it.
The bear's nose is quite a remarkable device.
Around nine inches long, for one thing,
it really is all the better to smell you with.
Their noses contain hundreds of miniature muscles
which they can manipulate with the same ease
as we might move our fingers.
The surface area inside their noses is also vast
by human standards and contains hundreds of receptors.
And they have that Jacobson's organ in the roof
of their mouth to round out this sensory arsenal.
But what about the age old question?
Can a bear smell your fear?
The answer is yes and no.
A bear can smell if you break into a cold sweat,
but it doesn't register this as fear per se.
So it's truer to say they can sense fear
rather than smell it.
On "Animal Super Senses" we touch it and feel it,
see it and hear it, taste it and smell it like animals do.
The senses are the star on this show
and this episode has been no exception.
Taste and scent are as vital in the wild
as they are in the world we've made for ourselves.
Maybe even more so.
But these incredible powers of perception
will fight again another day.
So join us next time on "Animal Super Senses".
(light dramatic music)