Natural World (1983) s29e14 Episode Script

Think of African elephants, and most of us will picture open savanna where the largest land mammal mingles with lions, giraffes and gazelles.
In fact, a third ofAfrica's elephants live here - in dense, dark rainforests.
(TRUMPETING) Forest elephants stand just two metres at the shoulder, are more slightly built, and have pinker tusks than those on the savanna.
Little else was known about them until one remarkable woman began eavesdropping on their lives.
Andrea Turkalo is no ordinary scientist.
By living alone in remotejungle, she's learned more about these hidden giants than anyone else on Earth.
This has placed a huge burden on her shoulders.
Forest elephants are now under greater threat than their savanna cousins.
But Andrea could be in a unique position to help them.
She's learned their language and understands what they're thinking.
She can even hear when they're in trouble.
Incredibly, she believes that if we listen carefully enough, they might tell us what they need to survive.
The only thing most scientists see of forest elephants is what they leave behind.
Counting dung piles has been the crude way of guessing how many there are.
Their real secrets are hidden away in the vast rainforest that stretches over the Congo Basin.
But in a small corner of the Central African Republic, there is a window into their lives.
(TRUMPETING) This is Dzanga Bai a vast, natural clearing and a Mecca for forest elephants.
(BIRD CHITTERS) (ELEPHANT TRUMPETS) (TRUMPETING) The forest provides all the food they need.
So what is it that draws them out of the shadows? (RUMBLING) The clearing contains a vital ingredient that's lacking in their diet.
Volcanic rocks lie close to the surface, and the salts they contain neutralise toxins ingested with rainforest leaves and bark.
(BUBBLES GURGLE) Blowing down, they churn up the mud, then take a mouthful of the mineral-enriched waters.
(RUMBLING) As soon as they've mastered their trunks, they're hooked.
It may be that these mineral salts are also vital for the elephants' growth and fertility which is why as many as 3,000 elephants visit Dzanga each year.
They'll try any tactic to control the best areas of the bai.
(RUMBLING) (PROLONGED CRY) Dzanga Bai is not the only clearing where they can get these salts, but it's certainly one of the biggest and most frequented.
When Andrea Turkalo first came here, she had an instinct that this place could help her unlock the secret lives of forest elephants.
ANDREA: I knew immediately that this was an extraordinary place, because to see wildlife in the open in the forest is impossible.
I went there first in 1 987 just to see the place, and actually slept there.
And all night there were these extraordinary elephant sounds, because elephants don't sleep like we do.
There was just this symphony of elephants, and in the morning they were still there.
It was obvious that this was probably one of the most special places for them in the Congo Basin.
Andrea now understands what the symphony means.
She can even hear an individual elephant's voice.
(RUMBLING) But back then, she was faced with a huge problem.
Each elephant visits forjust a few hours - at best, a few days.
So Andrea only had snapshots to go on.
(THEY TRUMPET IN TURN) - (PLAINTIVE WAILING) - ANDREA: Oh! - (AGGRESSIVE TRUMPET) - (ANDREA LAUGHS) (ROARING) She might not see them again for monthsor years.
From this constantly changing cast of characters, how could Andrea work out the big picture? (THEY TRUMPET AND RUMBLE) There was another challenge.
Andrea wasn't a trained scientist.
But she had been a teacher in the Bronx, one of New York's toughest neighbourhoods, and she was single-minded enough to commit herself long-term.
She left her family and friends and set herself up in the middle of nowhere.
At the beginning, I can honestly say there were a lot of things I was afraid of.
I wasn't comfortable in the dark.
You're always in contact with insects, and that was something I didn't like.
But you have to deal with it, and that's what I did.
Andrea's had to turn her hand to everything, building a camp from scratch and surviving on minimal creature comforts.
(ANDREA TALKS TO COMPANION) She's also had to place her trust in the local Bayaka Pygmies.
They come from an ancient tribe who have always lived in this forest.
They have helped her to adapt.
ANDREA: All my employees come from the local Bayaka tribe.
They have great forest skills.
They keep me out of harm's way.
They see things long before I even am aware of them.
NARRATOR: Every day, Andrea sets off with her loyal helpers on the 45-minute walk to the bai.
It's a routine she's stuck to for 20 years.
(ELEPHANT TRUMPETS) (RUMBLING) Today, like any other day, she has no idea who - or what - she might see.
(WAILING) ANDREA: Oh, my God! It's Gutki.
I can't believe she's come back.
I haven't seen her in about six months, and she's still able to keep up with her group and she's still walking.
(TRUMPETING) NARRATOR: It's not uncommon for calves to be born with disabilities.
What's unusual is that Gutki has survived for so long.
Unlike on the savanna, there are no large predators here, which might explain why.
But life in the forest for a disabled calf is by no means easy.
ANDREA: What really amazes me about this individual is, if you think about walking in the forest, the mother must come to obstacles like fallen trees.
So she's evidently accommodating the female with the handicap, because she's keeping up with the group.
Otherwise, she would just get lost in the forest - left.
(SNORTING AND BUBBLING) This place never ceases to amaze me - the things you see.
NARRATOR: Even though Andrea sees individuals only rarely, she's been able to piece together their life stories.
(RUMBLING) She couldn't have reached this extraordinary position without first learning how to pick out faces from the crowd.
By mid afternoon, the crowd can be 140 strong.
To keep track of so many individuals, Andrea drew pictures of their ears, which get ripped and torn in distinctive ways as they move through thejungle.
(GENTLE TRUMPETING) (RUMBLING) She had over 4,000 identity cards before she realised her phenomenal memory was taking over.
(TRUMPETING) ANDREA: I think the big breakthrough was when you realised you knew the elephants.
You felt empowered.
You could just go out there and look, and you knew them like you would see someone on the street in your home town and recognise them.
NARRATOR: Now her encyclopaedic mind holds details of countless unfolding family sagas.
(RUMBLING) During the hours she spends at the bai, she notes all the arrivals and, crucially, who greets whom.
It's late afternoon, and Andrea has noticed two related elephants who've arrived from different parts of the forest.
ANDREA: This is Mimi I, who's the matriarch of this group.
(RUMBLING) Mimi I knows that Mimi II is there.
They're heading right towards each other.
There we go.
There's a nice greeting going on right now - some very low frequency.
Yeah, now they're trunking each other.
Yeah.
Yeah - that's a mother and daughter.
Some of these greetings are very subtle, and if you know the individuals, then you can predict them.
NARRATOR: By understanding these relationships, Andrea's made an important discovery.
(SNORTING AND BUBBLING) In the forest beyond the bai, it's rare to see more than one elephant at a time.
People assumed they led solitary, independent lives.
Andrea believes that even though relatives might not stay together in the forest, they do appear to know each other's whereabouts.
ANDREA: I think there's a general misconception about forest elephants only having small family groups.
But they do have extensive networks, and they should, because we know that about savanna elephants.
Why shouldn't forest elephants still maintain these social groups? NARRATOR: Dzanga Bai, as well as offering medicinal salts, appears to be an important venue for elephant family reunions.
Andrea is beginning to understand why the Bayaka call this place "the village of elephants".
But even the Bayaka don't understand how the elephants appear to second-guess each other's movements - how they know when other family members will be at the bai.
To get to the bottom of this, Andrea has had to start thinking like an elephant tuning in to this forest world as they do.
(THUNDER RUMBLES) (TRUMPETING) A heavy storm prevents Andrea being at the bai, but even from her office, she can hear the elephants calling.
For two decades, she's spent more time with elephants than with her friends and family.
Even so, she's only witnessed a fraction of what they do.
Forest elephants spend only 5% of their lives at the bai, mostly at night, when Andrea's not there.
(THUNDER CRASHES AND ROLLS) (WAILING CALL) It's at night, when they're visible only by starlight, that the elephants are at their most sociable (SHARP BARK) and most vocal.
(RUMBLING) It's also when Andrea is most worried for them.
(GROANING) Huge reunions out in the open place forest elephants in grave danger.
Every year, one in ten of Dzanga's elephants is taken by poachers.
(THUNDER CRASHES) (ELEPHANTS RUMBLE) (BIRDSONG) (FLOCK SQUAWKS) Andrea's no longer here just to study them.
She feels a growing duty to protect them.
She believes their conversations are rich in meaning, and that one way to help is to listen to what they're saying.
Today she's adding to her vocabulary, and to get a better view of the clearing, she's working from a viewing platform.
ANDREA: We're up pretty high, about maybe seven metres.
And you can see one end of the bai from the other.
And you see all the entrances to the bai, so I'm able to keep track of all the individuals that come in.
NARRATOR: From up here, she can compile a kind of elephant phrase book, which links particular behaviour to the calls they make.
ANDREA: What I'm doing is I'm trying to capture vocal sequences between elephants in the clearing in order to build up an elephant lexicon with these vocalisations' meaning.
Because I know the individuals, I can also anticipate these vocal events.
(LOUD GROANING) Someone's lost.
It's probably a juvenile lost its family.
(INSISTENT MOANING) (DISTANT TRUMPETING) NARRATOR: An elephant's hearing is phenomenal.
They can hear much deeper sounds than we can.
(RUMBLING) Technology is helping Andrea to record these very low-frequency calls that are normally inaudible to humans.
(WHOOSHING) ANDREA: Yeah, Milo is checking out this female.
(RUMBLING) She's doing a very nice rumble.
(RUMBLING) Elephants often do that when a female is being checked out by a male.
They do this low rumble.
NARRATOR: Andrea can now identify ten different types of call.
She's even discovered that each family has a distinctive voice.
- (PLAINTIVE WAILING) - ANDREA: Oh! Separated from its mother.
(GROWLING) Oh, the mother's coming.
The mother hears the baby crying.
- (GENTLE TRUMPETING) - There she is.
She's vocalising.
There's a lot of low frequency going on now, reassuring the calf.
And probably the calf is learning the family's specific calls.
(RUMBLING) NARRATOR: Back in camp, Andrea can analyse the recordings and start to see the pattern of each elephant call.
- (YELP FOLLOWED BY WAIL) - This is a clip that I've pulled off to illustrate the distress call in a young calf.
It's crying, and it makes this sort of very low, mournful sound.
Um And what you'll see next is the response of two young, sub-adult females.
They approach the calf, and then they discover each other.
This looks like a small greeting, but then they go back and follow the calf, who's probably heard from its mother in the meantime and is approaching its mother.
NARRATOR: Each sound recording gets turned into a spectrogram giving Andrea a detailed picture of the call.
ANDREA: This is the calf's call.
And then you have these very low-frequency calls here.
You definitely see the calf calling - you see the mouth open.
But to know who's making those low-frequency calls is difficult.
But because the calf turned around and went in the other direction, I would assume it's the mother, and it recognised its mother's voice and now it's approaching its mother.
If you collected enough of these distress calls of calves of a certain age, you could compare them to see if this is your typical distress call.
NARRATOR: Andrea has developed an amazing skill.
By learning their language, she can interpret what they're doing.
This is a greeting between three members of the same family.
(LOW YOWLING) (CHIRRING) (TRUMPETING) They're all vocalising.
(TRUMPETING) They've all recognised each other and they've all grouped together, and the ears are flapping and they're trunking each other and they're excited to be together again.
So I assume they were separated for a bit of time, because of the, erthe energy involved in their vocalisations.
(LOW YOWLING) NARRATOR: Their rumbles can travel over a mile through dense vegetation.
Even though family members are spread out, they can hear an invitation to meet up.
(RUMBLING) Part of the call is inaudible to our ear - it's infrasonic.
But a lot of it is audible, and that's what we're hearing.
But these low frequencies are the ones that travel farthest through the forest.
So if they're having this greeting and there are relatives in the nearby forest, they'll hear it, and a lot of times, you see other family members show up.
NARRATOR: If their social networking is this powerful, they might even be able to warn each other of danger.
The following morning, the bai is eerily quiet.
(THEY WHISPER IN LOCAL FRENCH) He says that he's found blood on the trail and there's a lot of elephant tracks.
NARRATOR: Days like this remind Andrea how vulnerable these elephants are.
ANDREA: I can see blood right here.
He ran here, but you can see tracks all around.
There's more here.
(SHE SPEAKS LOCAL FRENCH) More here.
You can see where the elephant has trampled earth.
He's probably panicking.
He looks pretty big.
(SPEAKS LOCAL FRENCH) You can see track right here.
Pretty big male.
That's the track of the front leg.
NARRATOR: Most forest elephants have tusks.
The biggest adults carry the most ivory.
This is a big patch of coagulated blood.
It's pretty fresh, so it was from this night.
There's also a track.
Now they're saying it might be a female.
Where we are now is only about probably 30 metres from the bai.
But we suspect the elephant was shot on the other side and ran.
We didn't hear any gunshot, and generally somebody will hear a gun if it goes off.
NARRATOR: Dzanga Bai is within a national park, so all Andrea can do is report the incident to forest guards.
It's a hard place to police, but Andrea's very presence in the area does make events like this less frequent than they'd otherwise be.
Andrea wants local people to understand the value of elephants, notjust as intelligent, interesting animals, but because in their secret wanderings, elephants influence the shape and richness of the forest itself.
The richer they make the forest, the more food there is for everyone.
The most obvious way they do this is by engineering pathways through the tangle of vegetation.
Over time, elephant feet have created wide trails - highways that run for hundreds of miles through the forest and which link key resources.
ANDREA: We're walking along a pretty well-worn elephant track, and occasionally, areas open up like this because of the existence of this tree.
This is a particularly favourite tree of elephants - it's duboscia - and generally, where you find these trees the forest opens up because elephants come and eat the fruits.
It's a very fibrous fruit, and we find it generally in about 90% of the elephant dung throughout the year, so there's always a duboscia tree fruiting.
Not only do they eat the fruits, but they also scrape the bark off and eat that.
NARRATOR: Their trails are used by many other animals.
Western lowland gorillas eat the same kinds of fruits as elephants, so elephant paths are like signposts to food.
(ELEPHANT RUMBLES) But there's one type of fruit that only the elephants can get to.
Omphalocarpum fruits are encased in a tough shell, making them virtually impossible to crack.
(CHOMPING) Elephants have the perfect tool for thejob.
They may devour everything, but the seeds of all the fruits they eat pass unharmed through the gut.
(CRUNCHING) As they travel, the elephants replant the seeds, creating avenues of their favourite fruit trees.
Where there's a lot of elephant activity, areas open up, and sedges and grasses can take hold.
They are fundamental to the gorillas' diet.
These great apes would find life much harder without the elephants.
But the relationship isn't an amicable one.
(ELEPHANT RUMBLES) (BELLOWING) Elephants don't like other animals sharing the clearings they created.
As they dig for minerals, they actually maintain and expand these bais.
Over centuries, elephants have made hundreds of small clearings in the forest.
But none compares to the importance of Dzanga.
(TRUMPETING AND RUMBLING) It's now the dry season, one of the busiest, and for Andrea, one of the most fascinating times at the bai.
It's when most of the big bulls show off.
(RUMBLING AND SPLASHING) This is Triple Bite.
Over the years, Andrea has watched him grow from an adolescent into one of the most dominant bulls in the clearing.
But he hasn't been here for nearly a year.
He has travelled hundreds of miles to reach Dzanga, where he knows he can find females.
It's notjust the females that sense the tension rippling across the bai when the big males arrive.
(TRUMPETING) That's Gonya V chasing sitatunga.
(SHORT TRUMPETS) For the younger bulls especially, this can be a very exciting time.
ANDREA: The young elephants, they come and they're very feisty, and they'll just run around the bai for the entire afternoon.
He's like a young male in puberty, so he's learning how to be a male.
(TRUMPETING) (SNORTING) (TRUMPETING) NARRATOR: Unlike on the savanna, elephants rarely see each other in the forest.
This clearing offers rare moments of contact - time for the bulls to get to know each other and learn each other's strengths.
(RUMBLING) (BELLOWING) And everything they do is copied by the youngsters.
(THEY RUMBLE) (BELLOWS AND RUMBLING) ANDREA: A lot of learning going on here.
It's sort of like a school yard.
Elephants are so much like humans.
We learn to be human and end up being socialised, and elephants undergo the same process.
NARRATOR: Andrea calls this "bull school" a time and place to learn their position in elephant society.
ANDREA: When I started this study, I had no idea about how conscious they were, and yes, they do have good memories, and they have personalities.
Watching an elephant grow from childhood to adulthood, it's been astonishing to see the changes in how much they really have to learn to become and elephant.
(BELLOWING) NARRATOR: Andrea has revealed something even more significant about Dzanga Bai.
This clearing isthe place where elephant culture is passed on.
Understanding the central importance of Dzanga Bai places an even bigger burden on Andrea's shoulders.
Her presence here is notjust preventing elephant deaths, but the possible disruption of their entire way of life.
(RUMBLING) She wants to protect the elephants, but she has to work within a culture that has very different attitudes and priorities to her own.
For centuries, the local Bayaka have hunted forest wildlife for food, and Andrea is pragmatic about that.
ANDREA: Traditionally the forest, for them, has been their life source.
It's where they find everything they need.
You know, they eat elephant meat.
That's not a mystery to me.
NARRATOR: Andrea steers a difficult course between her feelings for the elephants and respect for the Bayakas' traditions and needs.
ANDREA: A lot of them will go into the forest for two or three months of the year where they'll gather honey and certain seeds that they eat.
And the people that work with me, I've made their work schedule very flexible, so they can tell me, "I want to go into the forest for the next three months, " and I'll say, "Fine.
" I think that's a very important part of their culture and they need to teach that to their children, because ultimately, it may be the only way they'll survive.
NARRATOR: Not many employers would be this flexible, but she believes it's the only way.
(WATER SLOSHES) ANDREA: You have to be there for them when they really need you.
Otherwise, they won't be there for you when you need them.
I think that's really sustained me here in many ways - that connectedness to people here.
NARRATOR: Andrea treats her Bayaka workers like family, making regular trips to buy them supplies.
The local village is only eight miles from Andrea's camp, but the round trip, on rough, dirt tracks, takes a whole day.
(INAUDIBLE) It's impossible to grow anything in camp, because elephants raid the crops at night.
The heat and humidity means nothing stays fresh for long.
OK, a c'est dix milles et cinq milles.
This is smoked fish.
If you buy it smoked, it keeps up to two weeks in camp without refrigeration.
I don't eat smoked fish.
It's an acquired taste.
Merci.
NARRATOR: Protein is difficult to come by.
What there is tends to come from the forest.
Local people are allowed to hunt outside the national park, but laws control which animals can be taken as bush meat, and how many.
Even so, Andrea knows there's elephant meat under the counter.
(HE SPEAKS LOCAL FRENCH) The guards that patrol the forest do their best to contain this black market.
More commonly, they pick up people who have taken too many animals, or who have the wrong licences for their weapons.
Most people arejust trying to feed their families.
Elephant meat is a delicacy, but it's rarely on the menu.
They are hard to kill with a normal shotgun.
And Andrea's workis making a difference.
When I first started working with the Bayaka, I think we all had this vision that they know the wildlife, but they didn't know elephants in the way that they've gotten to know them with me.
But because now they've spent many years observing elephants first-hand, their ideas have totally changed.
In fact, one of them said to me one day, "Madame, these aren't elephants - these are people.
" And it was very touching for me to hear that.
Sadly, local opinions are increasingly affected by bigger changes sweeping across the region.
Andrea's seeing more and more elephants entering the bai.
She thinks they're being pushed into Dzanga as commercial logging disrupts their extensive network of paths.
What's more, ivory is back in demand, and the tusks of forest elephants are most sought after.
They are pinker and much denser than those of savanna elephants, resulting in a rose ivory that's highly prized for carving.
Its value is astronomical.
A pair of tusks raises $90,000 on the black market.
It's no wonder some local people get drawn into poaching.
Human conflict in neighbouring countries floods the area with weapons.
The guards confiscate many of them, but there are plenty more, and they're largely pointing at Dzanga.
It's the easiest place to find and kill forest elephants unless, of course, Andrea is there.
ANDREA: I will react immediately to any threat.
I can be out at the clearing having a nice afternoon and then I hear gunshot and I'm gone.
I'm back to camp on the radio, trying to get guards motivated.
In many ways, Andrea is the only person standing between the elephants and mass slaughter.
After years of wanting to be here, she now dare not leave.
Even trips to the local town could endanger the elephants, because she's under surveillance too.
(ANDREA SPEAKS LOCAL FRENCH) Her absence from the bai never seems to go unnoticed.
The poachers are very localised.
They live in the village.
I know them.
They know me.
So when I'm driving out of town, they see me, and everybody It'd be people going, "Andrea!" by the side of the road! So they know I'm leaving.
And that's a worry, because there have been incidences where there is poaching when I've been gone.
This video was taken when I wasn't at the bai.
It was taken by one of the assistants, and he told me about this bull.
This is an elephant Andrea knows well.
But he now has a line of wounds across his flank.
He's a young bull - he's about 35 to 40.
His name is Hezy.
The wounds are definitely bothering him.
You see this often in elephants when they've been wounded - they'll spend a lot of time either throwing water on themselves or mud.
Cos those wounds are pretty deep.
I mean, they pierce the the epidermis, which is about a half an inch thick.
Andrea can tell from the pattern of wounds this was not the result of a fight.
That many wounds - I'd say a Kalashnikov.
Hezy has returned to the likely scene of the crime, perhaps because it's also the best place to treat his wounds.
But since this video was taken on May 1 3th, we haven't seen him.
So he might have even died.
He might have developed an infection from the wounds he sustained.
With the stakes becoming higher, even Andrea cannot live in such remote forest without protection.
She needs to share the weight of responsibility, and a chance has come.
She's been asked to help with a pioneering study at the other end of the elephants' range.
It means, for a few weeks, she will have to leave the elephants at Dzanga Bai.
Forest elephants inhabit a huge area, stretching over 2,000,000 square miles.
But there could be fewer than 1 25,000 left.
This is Gabon where the African rainforest meets the ocean.
It's considered to be one of the last safe havens for forest elephants.
It couldn't look more different from Dzanga.
Beyond the endless beaches, there's a mosaic of savanna, forest and swamp.
It's a new experience for Andrea.
She's used to seeing groups of over 1 00 elephants together.
Here, just seeing one is a challenge.
You don't see many, but when you do see them, they're doing extraordinary things I've never seen before in my life.
Elephants have adapted to this diverse range of habitats, even snorkelling across flooded channels and swamps.
This place gives me a lot of hope, in terms of elephant conservation, just because the elephants are inaccessible.
People can't hunt in these swamps.
And so that is a refuge for them.
However, there's no clearing like Dzanga to see elephants and monitor what they do.
Researchers have had to find a different way to tune into their lives.
MAN: We can put one somewhere around here.
Andrea'sjoined Peter Wrege from the Elephant Listening Project at Cornell University.
He's an expert in acoustic research, something he hopes will reveal more about forest elephants.
- So this is the hard drive - Yeah.
to store the data.
And then this is the computer - microcomputer - that's actually processing the sound.
He's putting up remote listening devices to eavesdrop on them.
But he needs Andrea's help, because only she can translate their calls.
PETER: We're still in kindergarten in learning exactly what their vocalisations mean and the social context in which they occur.
And this is where Andrea is so vital to what we're doing now is that she knows the behaviour of the elephants very, very well.
NARRATOR: These recording units contain state-of-the-art microphones, specially designed to pick up low frequency calls.
They can be left running for three months, 24 hours a day.
Each one records rumbles from over a square mile ofjungle.
It's better than CCTV.
That's OK.
So we're finished.
Ready to go.
PETER: It's absolutely a kind of spying on elephants - listening in on their conversations in order to understand what they're doing, how many there are, where they're going.
NARRATOR: Peter already has 33 of these bugging devices deployed in the rainforests of central Africa.
Now he needs Andrea's help to decode the latest recordings.
(ELEPHANT BELLOWS) (ELEPHANT BELLOWS MORE LOUDLY) - PETER: That's pretty deep.
- ANDREA: Mm-hm.
The different rumbles tell Andrea how many elephants are present and what they're doing.
OK, that, for me - this first call - may be an adult female.
And this might be a response to that call.
Let's try this one.
(ELEPHANT RUMBLES) (ELEPHANT BELLOWS) - This is a young animal again.
- Young animal.
Just by listening, she can tell which members of the family may be vocalising and why.
Would you call those all protest calls or? You said also sometimes No, I think they're lost calls.
I think they're separated.
So you're actually hearing a difference between a protest and a lost? Yes.
Those sounds like, to me, lost calls.
It starts low and it goes up.
The structure looks the same.
Yeah, well, that's one of the problems is, I need to know a little more from your ear, what do I need to be looking for tomake that distinction? (ELEPHANT BELLOWS LOUDLY) Andrea's knowledge will help Peter create a visual record of specific elephant calls.
He can then refer to this library and learn even more about elephant life here.
You don't have anything before that, do you? Recorded? Oh, I'm sure I do.
This is clipped out, though.
We could look.
It almost sounds like mating.
- Really?! - Yeah.
Because you've got a lot of these high-pitched things going on.
Without even seeing elephants, it's possible to translate their rumbles into information about breeding success.
(ELEPHANT RUMBLES) They've also revealed the dangers elephants face.
Before his study began, Peter was told there was no poaching in the area.
That's not the case.
These, I'm pretty sure, are high-powered rifle shots.
(CRACK) So these devices also spy on the poachers.
By pinpointing hot spots of illegal hunting, guards could target areas more strategically and efficiently.
- A lot of frogs.
- Mm-hm.
(CRACK) - Those are definitely guns.
- Yeah.
And again, this is a bit strange, because the intensity changes.
(SERIES OF QUIETER CRACKS) - That's a tree.
- Really?! That's a tree.
This first thing right here - this first sound you hear - it's the crack and then it's the "k-k-k-k-k-k".
- Hm, I don't know, Andrea - No.
No.
I'd put money on that on.
- (CRACK) - ANDREA: Hear that? (SERIES OF QUIETER CRACKS) And that's the whole thing going down.
It might get hung up on something.
- True.
- Yeah.
- A lot of trees out there.
- It's very complicated, tree fall.
- (PETER LAUGHS) - 20 years in the forest has taught Andrea what to listen out for.
And Peter knows the value of her extensive memory bank.
PETER: I am very concerned, actually, about the huge knowledge Andrea that has about these elephants.
I find it phenomenal what she remembers.
No-one else comes anywhere close to what she has.
So I think it is critical that we basically kind of extract this information from her brain.
NARRATOR: This experience has shown Andrea how her knowledge could help elephants across their whole range.
But she will always feel a strong connection to the individuals back at Dzanga that have been her life for so long.
I probably think about these elephants during my waking hours about 90% of the time.
I'm very concerned about them.
I mean, I feel it's my moral responsibility to be there.
Hopefully, when I get back, you know, the numbers will be the numbers I'm expecting to see.
When Andrea returns to Dzanga, there's depressing news.
More poaching has been reported in the area.
The demand for ivory is now threatening the very existence of forest elephants.
(ELEPHANT BELLOWS) Recent data has shown we've maybe lost between 40 and 50% of the population in the central Africa area.
So there's increasing pressure on this area where there are still animals left over.
Dzanga Bai continues to be a magnet for forest elephants and a privileged window into their lives.
That's Marnie.
Oh! There's a new calf! For the next 60 years, this calf could return time after time to take the salts, meet up with family and to find a mate.
(WHISPERS) That's nice.
That's a new baby for today.
He's trying to figure out what to do with his trunk.
But ifAndrea were to leave, who knows what upheavals he and his family would face.
I'm not an optimist about the future for animals here.
So, I mean, I get a little bit um emotional about it, but the reality is, these animals, if they're not protected, they'rethey're going to be poached.
For two decades, she has carried this responsibility on her shoulders.
But she cannot stay here forever.
I've been here for 20 years and I'm beginning to feel my age.
I think I'll stay here as long as I can walk and I can get support to do what I do, because I love this place.
I mean, there's a lot of downsides to my job, but coming here every day is is what makes it all worthwhile and just seeing them right here.
Maybe the pioneering study in Gabon will eventually take the pressure off her, and the remote listening devices will become her ears in the forest, allowing elephants to tell us of the dangers they face