BBC Learning English.

I’m Neil.

And I’m Sam.

For centuries the relationship between

humans and bats has been complex.

In some cultures bats are depicted as vampires,

associated with Halloween, witches and dark,

scary places.

In others they are considered

messengers of the gods.

Bats play an important part in stories and myths

from around the world.

And a large illuminated

‘bat signal’ shining in the night sky can mean only one thing –

a call for help to the superhero, Batman!

So do we love or hate these furry flying animals?

And with some newspaper headlines identifying bats

as the possible source of Covid-19,

should we think of them as friend or enemy?

We’ll be answering all these questions soon, but first,

Neil, time for another interesting bat fact.

Did you know that bats account for

1 in 5 of all mammal species?

There’s a huge variety of them, from tiny fruit-eating bats

that fit into the palm of your hand to giant carnivores,

or meat-eaters.

That’s right.

In fact it’s the variety of bat types that

might explain our complex feelings towards them.

So, Sam, my quiz question is this: roughly how

many different species of bat are there worldwide?

Is it:

a) one and a half thousand?

b) two and a half thousand? or,

c) three and a half thousand?

Hmmm, I’ll say b) two and a half thousand.

OK, Sam, we’ll come back to that later in the programme.

Maybe not everyone likes them but bats do have some friends.

Farmers love them for pollinating their plants…

…and medical scientists study them hoping to

discover the secrets of their anti-ageing and long life.

Dr Winifred Frick is the chief scientist at

Bat Conservation International, a group of

environmentalists working to protect bats.

Here she is telling BBC World Service programme,

The Documentary, about another useful service

provided by bats in the United States:

Most bats are insectivorous and they’re really

important consumers of different kinds of insect pests

and here in the United States it’s been estimated that

bats provide billions of dollars every year to the US

agricultural industry through their voracious

consumption of agricultural pest insects.

Most bats eat only insects – they’re insectivores.

That’s good news for farmers because they eat many pests -

insects or small animals that are harmful or damage crops.

Even better, bats’ appetite for these annoying insects is voracious –

very strong and eager.

So far, so good in the friendship between humans and bats.

But then along came the coronavirus pandemic and with it,

newspaper reports that bats might be to blame.

Before we get into this we need to explain some terms.

The Covid which people around the world have

been suffering from is the ‘outbreak virus’.

But if you go backwards there’s an intermediary

known as the ‘progenitor virus’ between this and

the ‘ancestral virus’, which is decades or centuries older.

Ninety-nine percent of scientists would agree

that the ‘ancestral virus’ of Covid-19 came from bats.

But it’s the go-between ‘progenitor virus’

that everyone is searching for now.

One of the scientists leading this search is Linfa Wang,

a professor at Duke Medical School who is known

as the ‘Batman of Singapore’.

Here he is explaining his

work to BBC World Service’s, The Documentary:

Of course the holy grail right now for Covid-19

is to discover where is that progenitor virus and

also in which kind of animals or humans, right?

And usually the progenitor virus has to be 99.9%

identical to the outbreak virus and so our study

was set up to do that.

If you can catch that virus

and you demonstrate the genomic sequence is

99.9% [identical] then that’s brilliant.

Professor Wang thinks that finding the source of

Covid-19’s ‘progenitor virus’ would be like finding

the holy grail.

This expression - the holy grail -

is associated with the cup believed to have been

used by Jesus Christ at his last meal.

It means

something extremely difficult to find or get.

If you can discover the ‘progenitor virus’ then,

in the words of Professor Wang – that’s brilliant! –

an exclamation meaning ‘that’s very good!’ or ‘amazing!’

So although bats are sometimes, wrongly,

blamed for causing Covid, they are good friends to farmers,

environmentalists and scientists – as well as vampires!

So anyway, what was the answer to your quiz question, Neil.

Ah yes, I asked Sam how many different species

of bat are there around the world.

What did you say?

I said there were, b) two and a half thousand

different species of bats.

Was I right?

You were close, Sam, but the correct answer was…

a) there are one and a half thousand different

species of bats around the world.

Let’s recap the vocabulary from this programme

about the relationship between humans and bats,

starting with carnivores which are animals that eat meat…

Insectivores, meanwhile, are animals,

like most bats, that eat only insects.

A pest is an insect or small animal

that is harmful or damages crops.

Bats eat pests voraciously, or very eagerly.

The holy grail refers to something that’s

extremely difficult to find or get.

And finally, you can use the phrase, that’s brilliant!

to say, ‘that’s great!’ or ‘amazing!’

Once again our six minutes are up.

See you again soon for more topical chats

and trending vocabulary here at 6 Minute English.

And don’t forget you can download our app

to find programmes on many more topics,

from African animals to zodiac signs and zombies,

all here on the BBC Learning English website.

Bye for now!

Bye bye!