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Visit qub.ac.uk and see how

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they are bringing research to

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reality. This

1:16

is the Science Podcast for December 8, 2023. I'm

1:20

Sarah Kresge. This week

1:22

we have two stories on thinking and

1:24

learning in animals. First

1:26

we have online news editor David Grimm. He's

1:29

going to take us to northern

1:31

Germany where researchers are studying cognition

1:33

in farm animals, cows, pigs, goats

1:36

and so on. And

1:38

because producer Kevin Kainers went along,

1:40

we have lots of audio from

1:42

the trip. So prepare yourself for

1:44

moves and more. Science

1:47

freelance producer Catherine Irving talks

1:49

with researcher Claire Spottiswood about

1:51

the mutually beneficial relationship between

1:54

birds called honey guides and

1:56

honey hunting humans. It

1:58

turns out that calls used by people to get

2:00

the birds' attention in order for them

2:02

to work together on a collaborative honey

2:05

hunt. They have co-evolved differently

2:07

from place to place, depending on

2:09

where the honey hunt is happening.

2:16

I've never been so nervous in my

2:18

life. It's been one of these, which

2:20

one doesn't belong games, which the goat

2:22

was solving with no difficulty. And every

2:24

time the goat gets it right, the

2:26

reward is some drinking water. I'm looking,

2:28

I'm staring at the screen. I'm not seeing

2:30

any differences between the four images. I'm starting

2:32

to sweat. David,

2:35

you can check out which picture

2:37

gives you water. They

2:43

look quite similar. Right. You're

2:45

smarter than a goat. Yeah, I

2:48

worry about that. If you're really smart, you need

2:50

four trots. Three, check out. And

2:54

these are images of goats? Like

2:56

face-on images of goats, or goat

2:59

heads. Okay,

3:01

so, but it keeps on moving around.

3:03

Let's see. There

3:06

was a right one. Yeah, the smart is a goat.

3:12

And then finally I picked up, you know, all

3:14

the goats had sort of these yellow tags on

3:16

their ears. Oh my gosh, you cheated

3:18

like an AI, you know, looking at tags instead

3:20

of faces. I've never been so happy to get a

3:23

squirt of water in my whole life. That

3:25

was our online news editor, David Grimm, describing

3:28

the harrowing experience of facing off against

3:30

a goat in an experiment where you're

3:33

supposed to tell goat faces appear on

3:35

a screen. This experience

3:37

was part of a trip he took

3:39

to northern Germany, where he visited researchers

3:42

studying cognition in farm animals

3:44

like goats, pigs, and cows. To

3:47

better transport us there, he brought along

3:49

freelance audio producer Kevin Caners.

3:51

They went to the facility, they met the

3:53

animals, and the researchers who were looking into

3:56

how the minds of livestock work and why we

3:58

don't know much about the way these

4:00

types of animals think. Dave, you've

4:02

been to a lot of research animal

4:04

facilities, places where people

4:06

study mice, places where chimps have retired,

4:09

even places where people have studied cats. How

4:12

is visiting this farm animal

4:14

cognition facility different from

4:16

all these other places that we've talked about

4:19

before? What stuck out to

4:21

you? Definitely had never been that close

4:23

and personal with pigs and

4:25

goats and cows before. This

4:27

facility that I visited, which is

4:29

the research Institute for Farm Animal

4:31

Biology, we call it FBN for

4:33

short, which is in Dümerstorff, Germany.

4:36

It's probably the biggest place in

4:38

the world that is studying farm

4:40

animal cognition. It's also got

4:42

probably the largest variety of animals,

4:44

lots of scientists studying these guys.

4:46

It doesn't really look like a research

4:49

institute, and it doesn't really look

4:51

like a farm. It kind of looks like

4:53

a cross between the two. I almost stepped

4:55

in a giant pile of horse poop, which

4:57

doesn't happen on your average research campus. These

5:00

are all animals that we've

5:02

domesticated for livestock purposes,

5:04

like for food, for

5:06

labor, for millennia. Why

5:09

don't we know that much about

5:11

how their brains work? Why don't

5:13

we know that cows could be

5:15

potty trained? Right. Right. Until recently.

5:18

This is probably one of the reasons I was

5:20

sort of most fascinated with the story. It's estimated

5:22

we've lived with goats for 10,000

5:24

years, which would make them the

5:26

animal we've lived with the longest,

5:28

except for dogs. Dogs may be

5:30

20,000 years. These aren't creatures

5:32

that we've only been living with for a few

5:34

decades. We've been living with them for thousands and

5:36

thousands of years, and yet

5:38

most people, even today, don't

5:41

really stop to think about how these

5:43

animals think. Do we

5:45

know why these kinds of animals,

5:48

livestock animals, haven't really been the

5:50

subject of much cognitive research? That's

5:52

what you talked to, but certainly some of the people

5:54

I spoke to think the reason is because we

5:57

don't want to think about how these animals think.

6:00

want to know if cows are

6:02

smart or pigs feel pain

6:04

or they feel terror or goats have

6:06

this very sophisticated conception of their world,

6:08

then what does it mean for the

6:10

way that we house them, especially on

6:12

factory farms? And so there is the

6:14

dismissive attitude of, well, of course, these

6:17

animals don't think let's not even bother

6:19

trying to figure that out, which I

6:21

think is what a lot of scientists

6:23

have had up until recently is

6:25

why would you even bother studying a goat or

6:27

a pig? That's a complete waste of time. What

6:31

are some of the broad questions that people

6:33

working in cognition at the facility, what

6:36

are they trying to figure out

6:38

about these animals? Well, you know,

6:40

it really runs the gamut. Some

6:42

of them are fairly basic questions

6:44

about emotions. Can these animals feel

6:46

happy or sad? Can they feel

6:48

optimistic or pessimistic? Can

6:50

they make friends? And then

6:52

much more complicated questions such as what

6:55

is their memory like? How long can they

6:57

remember things? Can they do some of the

6:59

things that dogs have been shown to do?

7:02

When we point at an object, dogs,

7:04

they really know what that point means. They

7:06

know that we're trying to show them something,

7:08

you know, and chimpanzees can't

7:10

do that. And so it's really remarkable that

7:12

dogs can. It's this really sort

7:14

of complex test of social intelligence and question

7:17

is can farm animals do that? I kind

7:19

of want to step through the three main

7:21

animals that you got to meet when you

7:23

were there. Let's actually

7:25

start with cows. What else are

7:27

people trying to learn about cows in the

7:29

facility? And how easy is it to

7:32

study these really large animals in the

7:34

research setting? Yeah, and that really gets

7:36

to the challenges. I mean, these animals

7:38

can be huge. These are also animals

7:40

that are often used to

7:42

being in herds. And so typically when

7:45

we conduct a scientific experiment, we separate

7:47

animals because we want to study them

7:49

by themselves. And that's fairly easy

7:51

to do with mostly lab animals we work

7:53

with. But when you get to animals that have

7:55

evolved to live in large herds, when you

7:57

separate them, they get really nervous and they

7:59

can take a really long time to get

8:02

them comfortable enough to participate in an

8:04

experiment. So Dave, I really thought

8:06

that we would hear a ton of mooing

8:08

and cow noise in the background

8:10

of your visit to this barn. And

8:13

there is some cow noise, like a light moo

8:15

here and there and some barn equipment noises

8:17

for sure. But actually, one of

8:20

the researchers pointed out that it's better that

8:22

the cows are not actually saying a lot.

8:26

Actually the cows do not vocalize so much

8:28

when they are in the barn because if

8:31

there is no special action

8:33

or no frustrating events or nothing,

8:35

then they don't have

8:38

any need to vocalize in

8:40

case you separate a cow from the herd

8:42

and put it in a restricted area for

8:44

certain reasons. Then they will start to vocalize

8:46

because they don't like it to be separated

8:48

from the herd. The cows that I

8:50

looked at, they had done some experiments with potty

8:52

training. Oh yeah, I remember. We did

8:55

a whole segment on potty training cows. This

8:57

team is also looking at friendship in cows. Do

8:59

cows form friends with each other? Are there cows

9:01

that other cows prefer to hang out with? Are

9:04

there cows that cows don't prefer

9:06

to hang out with? And what does that

9:08

say about what they're thinking about themselves and

9:10

kind of their social structure? I'm

9:13

Anka-Sine Pahl. I'm a doctoral student, so

9:15

I'm doing my PhD here at the

9:18

FCN in the project which

9:20

we called Cow Friends. So

9:23

the motivation of our project Cow

9:25

Friends is to find

9:27

close social bonds or even

9:29

friendships in dairy cows. We

9:31

already know that many species

9:33

of animals have close social

9:36

bonds or friendships. We already

9:38

know that friendships in animals

9:40

can decrease stress levels. We

9:42

know that animals that are

9:44

well integrated into their group

9:46

have increased birth rates and

9:49

that friendships between animals can

9:52

even increase the life expectancy of the

9:54

animals. And those nice

9:57

findings are not sufficiently studied in dairy

9:59

cows. cows so we don't know if

10:01

cows have friends yet. And

10:04

that's mostly going to be answered by getting

10:06

a sense of where they're spending their time.

10:09

That's the first step. And then

10:11

we want to see whether those

10:13

cows that are spending much time

10:15

together are alleviating stress better

10:17

than other cows. And how will you

10:20

measure stress? We are collecting saliva

10:22

samples and measuring cortisol. Also

10:24

measuring oxytocin, heart rate and

10:26

heart rate variability and

10:28

the behavior of course. The

10:31

cows are wearing these collars that have GPS

10:33

and does real time tracking of where they

10:35

are. You can see it

10:37

there on the length of a black cow. And

10:40

those are located by the sensors

10:42

every 1.7 seconds so that

10:45

we can have a precise picture of what

10:47

the cows are doing during the day. And

10:50

the research can figure out are there cows,

10:52

specific cows that cows like hanging out with?

10:55

And then what happens if we separate these cows?

10:57

And the teams found that when they reunite some

10:59

of these cows that they start grooming each other

11:01

and following each other around kind of like they're

11:03

cow besties. This particular

11:06

study is still kind of in its early stages

11:08

but there does seem to be some preliminary evidence

11:10

that there are, we call

11:12

it friendship but at the very least there

11:14

are preferences these cows have and

11:16

sort of who they hang out with. Now

11:19

the researcher we're going to hear from in a minute is

11:21

an applied ethologist. He studies the

11:23

behavior of animals in their natural

11:26

environment. And in the case

11:28

of cows we're talking the barn or a

11:30

farm. But we're also

11:32

going to talk about natural herd behavior which gets

11:34

to the question of whether or not cows have

11:36

friends. And so the next step

11:38

is how much of this herd behavior and how

11:40

much of their natural farm behavior needs

11:43

to be taken into account to keep

11:45

these animals happy and productive. My

11:47

name is Jan Langbren and I'm the supervise officer

11:49

within this project. And

11:52

I planned the experiments here we are doing

11:54

now on social cohesion in the groups of

11:56

cattle. cattle

12:00

in a group are

12:02

affiliated to each other. If

12:05

a cow has to change the group,

12:07

it might be better to transfer them

12:09

with their best friend to make it

12:11

easier for the cow to integrate into

12:13

the other group. Because as we

12:15

know from humans, it's quite easier if you

12:17

come to a different social

12:19

society or group, if you have a

12:21

friend with you or a companion. There's

12:24

some studies that suggest that cows that

12:26

are more stressed out, that are quote

12:28

unquote less happy, might be more

12:31

prone to disease, kind of like we are,

12:33

might give less milk. And so for

12:35

a farmer, it's not just a question of like,

12:37

I want my cows to be happy or less

12:39

stressed out. Even if you're just sort of thinking

12:41

about the bottom line of how much

12:43

milk or meat or whatever you're gonna get out

12:45

of these animals, it might also be too of

12:48

you to try to make these animals as happy

12:50

as you can. Dave also

12:52

took a trip to the pig barn and he

12:54

complained a lot about the smells. He

12:56

saw a pig voluntarily running on a treadmill and

12:59

also learned about piglet empathy experiments.

13:02

But besides being really big eventually and hard

13:05

to manage in that way, pigs are

13:07

also very smell oriented both ways.

13:10

You know, they smell, but they also pay more

13:12

attention to the sense of smell. They're

13:14

just not very visual animals,

13:16

which behavioral biologist Christian NaRout

13:18

realized when he started with

13:20

pigs, but eventually made the switch

13:22

to goats. Pigs do not focus

13:25

a lot on the visual sense, so it's really

13:27

hard to actually attract them and let them pay

13:29

attention to something visual going on in front of

13:31

them. And this was something really different for the

13:33

goats. So it was really easy to lure them

13:35

and have them isolated and test them in isolation.

13:37

And this was basically the point where I figured,

13:41

if you want to do something visual, if you want to,

13:43

the animals have a choice where they can choose something on the

13:45

left or the right side. Goats are

13:47

a perfect species for that because they pay a lot

13:49

of visual attention to what you're doing. With

13:52

goats, the thing isn't so much how much they smell.

13:54

It's how much noise they make. The

13:56

sound comes from the males who attack

13:58

the... a wall that separates them from

14:00

the male in the other box. They

14:02

want to fight. And as they

14:05

are not able to make direct contact,

14:07

they fight the walls, yeah. But

14:09

normally they are really cute, especially

14:12

the ladies, because we were all in

14:15

former experiments. So

14:17

they are quite happy to age it,

14:19

well, not to foreigners, right? Huh? Come

14:22

on. Come here, come, come, come,

14:24

come. Yeah. Those guys are

14:27

staring at me right now, right? They just stare

14:29

at you and you think, okay, I mean, at

14:31

some point I'd probably get boring, but no, they

14:33

just look at you all the time. Which

14:36

also makes them good species if you do some

14:39

visual cognitive paradox, because they, yeah, you see, they

14:41

pay a lot of attention. Goats are a good

14:43

model species in terms of just

14:45

being goats and doing their goat stuff, but

14:48

also they can be used to translate

14:50

it a little bit and see what ruminant

14:52

species in general do. We do not know

14:54

a lot about goats. So basically, young and

14:57

maybe two or three other people in the world or

14:59

groups in the world that had done some goat research

15:01

at that point. So there was still a lot to

15:03

discover, a lot to do with the goats. And

15:06

this makes them like a unique experience.

15:09

It's like you're having a feeling of

15:13

exploring the species and actually being

15:15

able to grab what they're capable

15:17

of and how they perceive the

15:19

environment. The goats

15:21

especially have been really important

15:23

for a lot of visual type

15:25

research. We talked about these pointing

15:27

studies that the researchers are

15:29

doing with goats where they've actually found

15:32

that goats also respond to pointing, not

15:34

quite as well as dogs, but certainly

15:36

better than chimpanzees do. And so that's

15:38

pretty remarkable considering that the

15:40

idea with dogs is they're so attuned to

15:43

our social cues because

15:45

they've evolved so closely with us for

15:47

20,000 years and we so

15:49

heavily domesticated them to be companions and helpers.

15:51

And of course, they're gonna understand

15:53

our social cues. One

15:56

of the amazing things that goats can do

15:58

is they can look at screens. with

16:00

images on them and tell if it's

16:03

goat faces, if it's human faces, they can

16:05

tell them apart. These researchers have come

16:07

up with a way for them, for the goats

16:09

to convey that. It's almost like the goats have

16:11

like an iPad or something. Normally,

16:13

if you want to study learning

16:16

behavior in animals, we

16:18

have a group of animals, of single animals

16:20

in the normal housing environment, takes them out

16:22

and brings them in the experimental environment where

16:24

you present the learning task. And

16:27

it's totally different here. We bring the learning

16:29

tasks into the normal housing conditions of the

16:31

animals. The learning computer

16:33

we installed here is part of the normal

16:35

pen where they live all the time. They've

16:38

got these computer screens, these

16:40

thin computer screens in their

16:42

enclosures that are on sometimes 24 hours

16:45

a day, and they're just flashing different pictures.

16:47

Sometimes there's like four pictures of goats and

16:49

they all look almost identical, but there's one

16:51

tiny difference and the goats have to sort

16:53

of figure out which one is different. Sometimes

16:56

it's like a memory game where goats

16:59

are presented with a whole series of images

17:01

and they have to remember the order, which

17:03

they can do sometimes weeks later.

17:05

In one case, they remember the sequence of

17:07

24 different images, I

17:10

believe up to maybe a month

17:12

or so later. I definitely

17:14

cannot remember images in order

17:16

that long after it happened. But

17:19

just to change the topic for a second here, when

17:21

you did your goat facial

17:23

recognition test, you were

17:25

rewarded with water, but water

17:28

is not the only treat these goats

17:30

get. There's also this very special

17:32

carb. Yes, they get dried

17:34

pasta, I think it's dried

17:37

penne pasta, and apparently

17:39

they love it. I think one of his

17:41

and he would even come up to you.

17:43

So just one. Yeah,

17:45

just one. Yeah,

17:48

just one. Yeah,

17:50

just one. the

18:00

goats making one of the most

18:02

constant ones with this crunching sound. Well

18:08

much of the research at FBM that

18:10

we've talked about so far has really

18:12

focused on getting a deeper understanding of

18:15

livestock cognition, how their brains work, looking

18:17

at emotions, perception of the

18:19

world. There's also research that

18:21

is trying to fold this

18:24

new understanding of the animals

18:26

capabilities into ways of

18:29

improving conditions of livestock outside

18:31

the laboratory setting. Dave,

18:33

what are some of the things that might change

18:36

if this research influences

18:38

or reaches farmers or

18:41

even regulators? It might

18:43

influence how farmers sort of separate

18:45

or don't separate their cows for

18:47

the goats. We're talking about chimpanzees

18:49

or even lab animals. We talk

18:51

about enrichment, this idea that it

18:54

may not be good for them mentally to sort

18:56

of be sitting in these barren enclosures all day

18:58

with nothing to do and nothing to play with

19:00

or nothing to figure out. These

19:02

goats, there's been some studies to

19:04

show that even if they don't

19:06

have to play with these things

19:09

to get food or treats, they do it anyway.

19:11

So there's some sort of enrichment,

19:13

there's some sort of pleasure in just

19:15

trying to figure out a puzzle. So

19:17

one could imagine on a farm, maybe

19:20

touch screens are not right around the corner,

19:22

but this idea that giving these animals something

19:24

to figure out to get their food. This

19:27

is done often with zoo animals now where

19:29

they have to use these puzzle feeders even

19:31

to get their their meals.

19:34

Do you think farmers already know some

19:36

of this stuff that the researchers aren't

19:38

just now learning? Well I think

19:41

they do and actually that's something that

19:43

one of the scientists, Jan told me

19:45

was that he thought, especially younger

19:47

farmers, not only do they know this

19:49

stuff, but some of them are actually

19:51

very receptive, especially on the smaller farms,

19:53

to whether it's enrichment

19:55

or other things, really acknowledging that

19:58

these animals aren't just production

20:00

units but that they have these sort

20:02

of inner mental and emotional lives that

20:04

sort of need to be nourished. I

20:07

was trained, I was a trainer as

20:09

a cattle breeder 30, 40 years ago,

20:11

okay maybe more and

20:13

at that time nobody talked

20:15

about animal welfare or how

20:18

do they feel or do they

20:20

have emotions and have the personality.

20:22

Nobody had asked this question at

20:24

that time. Now we have heated

20:27

water beds for piglets and we have

20:29

brushes in the barn for the cattle

20:31

to feel better and they use it

20:33

a lot. Even though the animals are

20:35

now allowed to move freely in the

20:37

barn, nobody use tie stones anymore. All

20:39

this is progression in the

20:41

sense of higher welfare for the animals

20:43

but it goes step by step and

20:45

sometimes not so fast that we wish.

20:49

Okay Dave, what's next for this

20:51

field of farm animal cognition? What

20:54

other questions are out there and what

20:56

kinds of experiments would these researchers like to

20:58

do? Well you know now

21:00

that we've got artificial intelligence which could

21:02

sort of help with trying to figure

21:04

out where these animals spend time and

21:07

who they spend time with. Eye tracking

21:09

technology which is intriguing but also difficult.

21:12

Goat eyes are really kind of on

21:14

the side of their head you know and eye

21:16

tracking technology we've got right now is

21:18

for animals, mostly humans that have our eyes

21:20

in the front of our head right? That's

21:23

really interesting. There's also plans in the

21:25

works by these researchers to somewhat follow

21:27

the path that dogs have taken.

21:29

You know we've learned a lot about dogs

21:31

in the last decade by using MRIs and

21:34

doing other kinds of puzzle studies, eye gaze

21:36

studies. We basically know a

21:38

lot about these so-called smart animals, dogs,

21:40

chimps and dolphins but we're

21:42

really just getting started with goats. So

21:45

moving in that direction like what do the

21:47

animals expect when they see a situation popping

21:50

up here? What do they anticipate? And this

21:52

will also for example not only inform us

21:54

about goat behavior or goat biology but also

21:56

how we interact with these animals. So how

21:58

do they see humans? can

22:00

they anticipate human behavior? And if they can,

22:03

we should adopt their own behavior to their

22:05

ability. Super

22:07

interesting. You know, most of the

22:09

goats I've interacted with have definitely given off

22:11

kind of a Wiley vibe. I really

22:14

hope you enjoyed your trip, Dave. Thanks, Sarah. David

22:17

Grimm is the online news editor for

22:19

Science. You can find a link to

22:21

the story and related photos at

22:23

science.org/podcast. And special thanks to

22:26

Kevin Caners for all the

22:28

wonderful audio that he captured for us. Up

22:34

next, stay tuned for a conversation

22:36

between producer Catherine Irving and researcher

22:38

Claire Spottiswood about how

22:40

honey guide birds communicate with honey

22:42

hunting humans in different parts of

22:44

Africa. Finding

22:59

a beehive in a tall, dense forest is

23:01

a bit like finding a needle in a

23:03

haystack. That is to say,

23:05

it's pretty hard. Across Africa,

23:08

however, people from dozens of different regions

23:10

have found a better way. Wild

23:13

birds called honey guides that lead them to their

23:15

prize. This week in

23:17

Science, Claire Spottiswood and her colleagues

23:19

report a new discovery about this

23:21

fascinating human-animal relationship that

23:24

could indicate a cultural connection across

23:26

species. Hi, Claire. Welcome to

23:28

the podcast. Thank you very much. So

23:30

your paper focuses on the relationships

23:32

between these honey hunters and these honey

23:34

guides. What exactly is a

23:36

honey guide? There are specific species of

23:38

bird, is that right? Yes, the honey

23:40

guides are a family of wax-eating birds

23:43

that live in Africa and Asia that

23:45

are most closely related to woodpeckers. They're

23:47

in the paciform order, and

23:49

they're unassumingly drab and mostly quite

23:51

inconspicuous. But they do have some

23:53

really remarkable interactions with other species.

23:56

Fascinating. I didn't know they were

23:58

so closely related to woodpeckers. What

24:00

benefit does this bird get from helping

24:02

people and how does that relationship work

24:05

exactly? What honey guys get out

24:07

of the relationship is wax. It's one of

24:09

the many odd things about honey guides is

24:11

that they have the ability to digest wax

24:13

and obtain energy from it. It's a

24:15

really calorie-rich food if you have that ability.

24:18

So honey guides have a shared

24:20

interest with human honey hunters in bees nests. Honey

24:22

guides are brilliant at finding bees nests concealed in

24:24

trees, but they can't get at the wax, whereas

24:26

human honey hunters aren't nearly as good as honey

24:29

guides to find a bee's nest, but they have

24:31

the ability to subdue the bees

24:33

with smoke and open their nests with axes.

24:35

So by working together, the two species can

24:38

both find and access bees nests in

24:40

an exchange of information for skills. Got

24:42

it. So each of the different

24:45

species has a trait that the

24:47

other one lacks that helps them

24:49

work together. That's exactly right. They're

24:51

perfectly complementary. That's so cool. And

24:53

who initiates these collaborative

24:55

work usually? Is it the bird that

24:57

initiates or is it the person that

25:00

initiates? Your question highlights how communication

25:02

is crucial because honey guides use

25:04

chatarim calls to attract the attention of humans

25:06

and show them the way to a bee's

25:08

nest. Sometimes you'll be walking through the bush

25:10

and a honey guide will appear out of

25:12

nowhere and use these strident chatarim calls to

25:14

attract your attention and indicate to you that

25:16

it wants to cooperate and it's got a

25:18

bee's nest to show you. People

25:20

do also actively initiate cooperation

25:23

by using specialised calls to

25:25

signal that they're looking for a bird

25:28

with whom to cooperate and also to

25:30

maintain the bird's attention as they move together

25:32

through the landscape in pursuit of a bee's

25:34

nest. What's remarkable about these

25:36

specialised human calls is that they vary

25:38

culturally across Africa. So in some places,

25:40

people use beautiful, whistled melodies to attract

25:43

honey guides, whereas in others, they use

25:45

other kinds of whistles made with instruments,

25:47

such as snail shells or dried fruit

25:49

and in other places still. People

25:51

use various vocal trills and grunts and

25:53

whips and even sometimes words. So

25:56

at any one location, people will use just one

25:58

or a few. signals, but the

26:00

signals they use differ among locations according

26:03

to different human cultures. Fascinating.

26:06

And do you know how long these

26:08

sort of interactions have been evolving? Like,

26:10

how long has this relationship existed? It's

26:12

an excellent question. And of course, one

26:14

that really intrigues us. It's possible that this

26:16

relationship is extremely ancient. So the two

26:18

traits that make us particularly helpful and complementary

26:20

collaborators to honey guys, which are the use

26:23

of fire, to produce smoke, to subdue

26:25

the bees, and the use of tools to

26:27

open their nests and expose the honey

26:29

and the wax are skills that are even

26:31

more ancient than our own species. They

26:34

most likely perceive modern humans and evolved in the

26:36

region of 1.5 million years

26:38

ago to over 3 million years ago

26:40

in the case of tool yeast. So

26:43

it's entirely possible that human-honey guide interactions

26:45

have been occurring every day for even

26:47

longer than we've been human. So

26:50

you have some recordings of these calls

26:52

between the honey guides and the honey

26:54

hunters. So we could go ahead

26:56

and listen to those now. So

27:11

why don't you walk me through sort of what's

27:13

happening in this clip, what we're hearing? Well,

27:16

you'll have heard two very distinctive sounds on

27:18

that clip. One is the chattering of an

27:20

adult female greater honey guide who's chatting to

27:23

a Hudson honey hunter

27:25

named Margola Dungay.

27:27

And Margola has attracted this bird by giving

27:29

a whistled melody much like the one that

27:32

you heard him doing in the clip. And

27:34

he and the honey guide are following each

27:36

other through the bush in pursuit of the

27:38

bee's nest. So the bird is flying on

27:40

ahead giving that chattering call. And Margola is

27:42

responding with the melody that serves at this

27:45

particular point in the hunt to reassure the

27:47

bird that he's following and to maintain its

27:49

attention. That's amazing. And you

27:51

mentioned earlier that these calls

27:53

vary regionally and geographically. And

27:56

your paper actually argues that these honey guides

27:58

can tell the difference between them. that

28:00

they'll respond better to some calls than

28:02

others. So what made you

28:04

consider that these birds could differentiate those sands

28:06

in the first place? So we knew from

28:09

our past work that at least at one

28:11

location in Mozambique, honeyguides do seem to respond

28:13

appropriately to the local signal that's given to

28:15

them by, in that case, Yarl honeyhunters. And

28:17

our experiments there confirmed what honeyhunters already know,

28:20

which is that honeyguides are more likely to

28:22

come and invite you to cooperate if you

28:24

make a local signal. But what

28:26

we didn't know is how honeyguides would respond to

28:28

a foreign signal that's used to attract honeyguides in

28:30

another part of Africa. So if

28:32

honeyguides learn to recognize the local signal

28:35

systems, honeyhunters learn to produce them, then we'd

28:37

expect honeyguides to respond strongly to

28:39

local signals, but weakly to foreign signals.

28:41

But alternatively, there might be something about

28:43

these sounds that's just intrinsically attractive to

28:45

honeyguides by appealing to some bias in their

28:48

sensory systems such that they'd respond strongly to signals

28:50

from other parts of Africa too. Got

28:53

it. You're wondering whether the honeyguides

28:55

were responding to the call because it

28:57

was naturally intriguing or whether it's because

28:59

they had learned the specific

29:01

call of the local area and had learned

29:03

that that was the one that they should

29:05

respond to. Exactly, yes. So

29:08

you traveled to Tanzania and Mozambique to

29:10

conduct what you call simulation honeyhunts, which

29:13

is where you would play these different human sounds

29:15

and see how the birds would respond. So

29:18

what was that experience like? Yes, it was a

29:20

real joy. Both of

29:22

those places are very close to

29:25

our hearts. This research is a

29:27

beautiful and vast Nyatva special reserve

29:29

in the north Mozambique where Yau

29:31

honeyhunters attract honeyguides with their specialized

29:33

sound, which is a loud trill followed by a

29:36

grunt. And the second site

29:38

was Canary Hills in the north of

29:41

Tanzania, where pazza honeyhunters attract honeyguides

29:43

with the beautiful whistle melody that you heard on the

29:45

clip a moment ago. And in both of these places,

29:47

we as researchers have had the privilege

29:50

of being inspired by and collaborating

29:52

closely with resident honeyhunters for many

29:55

years now. So what exactly

29:57

did you do to try and test these

29:59

different calls? What was your

30:01

day-to-day routine like? We predetermined the

30:03

start points of around 75 transits

30:06

at each location and then when

30:08

we would reach by car the

30:10

start point of upper transits, we

30:13

would randomly allocate a treatment type

30:15

to that particular simulated honey hunting

30:17

trip. And these three treatments were

30:19

either the local honey hunting call,

30:21

a foreign honey hunting call, or

30:23

a control sound, which was an arbitrary human

30:26

sound. We would then walk through the bush in as

30:28

straight a line as we could, given the practice

30:30

of dense bush and the occasional incidents with elephants causing

30:32

a bit of a dog leg. And

30:35

then we would play back that one sound type on a

30:37

loop on a calibrated speaker and then

30:39

listen very carefully as we walked for honey

30:41

guides coming to guide us. And on all

30:44

of these walks, we were accompanied by two

30:46

honey hunters from the local honey

30:48

hunting community who were charged

30:50

with telling us as soon as they heard a honey

30:53

guide, which of course they're extremely

30:55

attuned to detecting. From this

30:57

experiment, you write that at

30:59

least in Tanzania, these honey guides are more than

31:02

three times more likely to respond to the sound

31:04

of the local honey guide calls than to

31:06

either the foreign calls or any random

31:08

human sounds that you play. That must have been

31:11

pretty significant to find.

31:13

It's almost uncanny, especially

31:16

in Tanzania where we hadn't done

31:18

this kind of experiment before and where the

31:20

pattern was so very strong. It was literally,

31:22

yes, uncanny is really the best word I

31:25

can use to describe it. These HUDSA cooperating

31:27

honey guides were really barely interested in the

31:29

foreign signal from Mozambique and

31:31

also not all that interested in control

31:34

human sounds either. So that

31:36

evidence really did strongly rule out the

31:38

idea that these signals are intrinsically attractive

31:40

to honey guide in any particular way.

31:43

And instead would appear to support the idea

31:45

that honey guides learn the local signals just

31:47

as humans do. So in summary,

31:49

data really best support the hypothesis that

31:51

just as humans learn the local traditional

31:54

honey hunting calls of their own culture,

31:56

so too do honey guides. That's amazing.

31:58

It really reflects on the

32:01

ability of at least this bird species to

32:03

kind of learn behavior and learn to hear

32:06

these calls. And yeah, it's

32:08

fascinating to think about how they do that, whether

32:10

they're growing up hearing those sounds and knowing that,

32:12

or whether they have to learn over time, each

32:15

of them individually. It is really intriguing. And one of

32:17

the reasons that it's intriguing

32:19

is that while people typically learn the

32:21

local honey hunting signals from their fathers,

32:23

this is what we're consistently told in

32:25

many honey hunting communities in Africa, we

32:28

can be pretty sure that the honey guides aren't doing

32:30

that though, because they're never knowing the meepers and parents.

32:33

They breed parasites like petus and cowbirds,

32:35

so they're raised by other species that

32:37

don't have any such relationship with humans.

32:40

So their own chattering guiding calls are

32:42

very similar across Africa. Those are parts

32:44

of the behavior we think are innate

32:46

to the greater honey guide as a

32:49

species. But their understanding of the local

32:51

human calls could be learned through some

32:53

combination of personal experience, but also perhaps

32:55

watching other more experienced honey guides and

32:57

acquiring them through social learning. So you

33:00

mentioned in the paper that you're finding

33:02

reinforced this concept that you

33:04

write about called cultural co-evolution.

33:07

So could you kind of explain what that

33:09

is and how it applies to the honey

33:11

guides and the honey hunters that you've been

33:13

studying? Yes, so our findings, we feel, are

33:15

consistent with the idea that learned how the

33:18

patients in different species can reciprocally influence and

33:20

reinforce each other in a way that's in

33:22

many ways akin to genetic co-evolution between species.

33:25

So in genetic co-evolution, genetically

33:27

inherited adaptations in different species

33:29

reciprocally influence each other. This can lead

33:32

to rapid genetic evolution and the shaping

33:34

of some of the most beautiful adaptations that we see

33:36

in nature. In

33:38

cultural co-evolution, instead of genetic adaptations

33:40

reciprocally influencing and reinforcing each other,

33:42

we may have learned and in

33:44

many cases, culturally inherited adaptations

33:47

in different species that reciprocally

33:49

influence and reinforce each other.

33:51

What's striking about this process is

33:53

that it can lead to mutual adaptation

33:55

on a very rapid time scale. It

33:58

is much faster than genetic co-evolution. but

34:00

also that just as traditional genetic evolution

34:02

can drive genetic biodiversity as

34:04

species interact, perhaps such a process

34:07

of cultural covelition could drive cultural

34:09

biodiversity. And this is an idea

34:11

that we'd love to investigate more fully in the future.

34:14

That's a really interesting concept, especially that

34:16

it applies to people. Usually

34:19

when we think of human relationships with animals,

34:21

we think about domestication or animals

34:23

under the control of the person, and

34:25

we specifically breed that animal to want

34:27

to work with us. In this case, it's

34:29

a wild animal that has chosen to

34:31

work with people. So it's this reminder

34:34

that we're not necessarily above the

34:37

ecosystem. We're still very much involved

34:40

with these relationships. It's really kind of

34:42

amazing to see that still happening in

34:45

our world. You put your finger on

34:47

it there that what's remarkable about this

34:49

form of cooperation is that it's evolved

34:51

through natural selection, not through coercion or

34:53

training or domestication, like

34:56

most of the other examples of humans

34:58

and other animals communicating with each other.

35:00

This has evolved because it provides a

35:02

mutual benefit to both species, not one

35:04

species exploiting the other through these various

35:06

means. Yeah, that's kind

35:08

of amazing and wonderful to see

35:11

that there's this relationship that can

35:13

still occur. What do

35:15

you hope that your research does for

35:17

people's understanding of these human-animal relationships as

35:20

a whole and about the Honey Guide-Honey

35:22

Hunter relationship? In a world in

35:24

which we're often hearing about the innumerable forms

35:26

of conflict between humans and nature, I really

35:28

hope that this research will help others to

35:31

share some of the joy

35:33

and awe that you just expressed that such positive

35:35

and cooperative relationships between humans and

35:38

nature can also exist and highlight

35:40

how we humans are integral part

35:42

of the ecosystems in which we

35:44

ourselves evolved. In addition,

35:47

I think an appreciation for the

35:49

cultural richness that's woven into such

35:51

relationships will make us value every

35:53

one of the remaining examples of

35:55

cooperation between Honey Guides and a

35:57

variety of human cultures across Africa.

36:00

ensure that we as a society do

36:02

what's required to ensure that these relationships

36:04

can continue in a rapidly changing world

36:07

that's quickly bearing down on them. Thank

36:10

you so much for coming on the show, Claire. Thanks

36:12

very much. Clare Spottiswood is

36:14

an evolutionary biologist at the University of

36:16

Cambridge and the University of Cape Town.

36:18

You can find a link to the

36:21

paper we discussed at science.org podcast. And

36:25

that concludes this edition of the Science

36:27

Podcast. If you have any comments or

36:29

suggestions, write to

36:32

us at sciencepodcasts.org.

36:35

To find us on podcasting apps, search

36:37

for Science Magazine. Or you can listen

36:39

to the show on our website, science.org

36:43

podcast. This show was

36:45

edited by me, Sarah Crespi, and

36:47

Kevin McLean with production help from

36:49

PataG. Special thanks to Kevin Caners for

36:51

his work on the farm animal cognition

36:54

segment, and of course, Katherine Irving for

36:56

her lovely honey guide interview. Jeffrey

36:58

Cook, composer music, on behalf of Science

37:01

and its publisher, AAAS, thanks for

37:03

joining us.