When you do hear a lion roaring, it just goes straight into your soul.

When they do that it tells others to back off.

My whole body is shaking from hearing that noise.

Lions make a variety of other sounds such as grunts, snarls, hisses, and even a meow.

But the lion's roar is the most famous.

It's amazing how that noise just travels through your body and like it, like, it makes me shake.

It's an iconic sound of Africa.

We've evolved alongside lions for millions of years and for a good portion of that time, lions' roaring has struck fear into us.

It really makes your tummy rumble and your toes twitch and your hair stand on end.

It's super loud and you vibrate when they roar next to you it's like bbbrrrr, you can feel it moving through you which, I don't care how loud the largest human is, there's no way that's going to happen, you know.

Vocalisation for lions in the delta, of every lion population, is, is really important.

It's actually, it's designed to intimidate.

It's also sort of designed to avoid confrontation.

Rather than walking about blindly and bumping into other male lions, roaring is a way to actually stake your claim on a, on a territory.

I mean, that's, that's not just a call.

That's an announcement.

Intimidation through roaring is one way of keeping rivals away, lessening the chance of a dangerous fight.

This is the kind of activity you would see from new males coming into an area, trying to claim that, very brazen, very sort of letting everybody know you're here.

As well as claiming land, these roars can be to coordinate with the pride or to attract potential mates.

Lions can figure out the size and threat level of a male from their roar, being heard up to eight kilometers or five miles away.

Most commonly roaring at night or first thing in the morning.

Just last week, I think it was, I could hear a lion roaring close to me and then base camp radioed in and said "oh okay.

I can hear a lion roaring to the east" and I thought, must be a coincidence, because camp is over five kilometers away and then the roar struck up again.

And then camp was like, "yep, I can hear the lion".

It was the same lion.

From squeaking to roaring, the repertoire of big cat vocalizations is large, and they have specialized equipment to do it.

So the cool little adaptation that allows a lot of the big cats to roar is a larynx or voicebox that's able to expand a lot more than in other animals and it allows for sound to project out at a much higher volume and deeper tone.

Their specialized voicebox has a floating hyoid bone, which makes this possible.

But cheetah don't have this adaptation.

Cheetahs are actually the only big cat that can't roar, and not many people know that.

They do make noises though.

Cheetahs' calling is very rare to hear.

Despite months or years in the field, many of the team had never heard it before and were surprised at what it sounded like.

Yeah, I've not really heard cheetahs chirping before.

That could be it.

The sounds that they make are called chirping, and that's because they sound like birds.

You could definitely mistake that for bird.

Wow.

It's beautiful.

First time I've ever seen a cheetah contact calling.

Sounds like a bird chirp.

[Laughs] That's amazing.

You can't imagine that a big cat could make such a sweet sound.

It's just, like, a little "neow".

Absolutely incredible.

But the cheetah chirp isn't the only surprising sound you might hear echoing across the Okavango Delta.

Another big cat here has another unusual vocalization of its own.

Leopards have two main vocalizations.

They've got a, kind of roar, which is very guttural and very, it's like a rasping noise.

It's, it's like wood sawing.

Very sharp, very short.

It doesn't just sound like wood sawing.

These unique leopard vocalizations are actually called sawing.

These roars are unique to each individual leopard who can be recognized through their voice.

The males obviously do it a lot more, as it's a dominance thing and kind of letting all the other males know that this is their place.

They don't just want to be roaring to let everybody know where they are.

It's about avoiding conflict, territorial stuff.

Although leopards typically use roars to defend territory or attract mates, this distressed female was roaring after losing one of her own.

This can be dangerous.

For her, unlike a lion, she's not the top predator out here, and her own species could be a threat.

She's very cautious, considered.

Very secretive.

She likes to go unseen and her actions now is broadcasting her presence and a sense of vulnerability in this area.

And it's going to attract male leopards, potentially hyenas, lions.

But I think she feels she's got no choice.

And then the other one's kind of like a cute little meowing.

You won't receive the males doing it.

You never really see them doing it.

It's all mums and cubs.

And the sound is, is almost inaudible to us.

It's like, "oh, oh".

And she'll call once or twice only and then sit there.

And that cub, could be 500m away from it, and it'll hear that little squeak, and the next minute it'll come barreling in.

Vocalizing is a great way of publicly communicating over a distance, but for really informative messages, scent marking tells cats of all species, a lot more.

You're not going to get a lot of information about me just based on how I speak, whereas you would find a lot more about me from my scent, be it from urine or something like that.

There's a lot more going on there that they can interpret a lot more detail about individuals.

And leaving these messages for each other means they don't have to be in contact to communicate.

It's a combination of scent and vocalization that makes up big cat communication.

A sort of language that we're still trying to decode.

I mean, vocalization in my book, it plays so much more of a significant role than we understand.

And the more I see it, the more I'm intrigued by to what extent that vocalization happens, and what it means.