[Greg] They're swimming.

Oh, my gosh.

[Narrator] They've never had to swim before.

[Greg] The cubs are panicking.

They can easily attract crocodiles.

[Narrator] Greg is with the Xudum pride and a large herd of buffalo.

[Greg] If there was ever a place that I wouldn't want to be as a lion, it's here, stuck between all of those buffaloes and a big river channel.

Despite the fact that buffaloes are food for the lions, they're also very much foe.

They can kill lions, and they often kill lions.

[Narrator] The lions still haven't eaten and now they're the ones being challenged.

[Greg] It's a wall of horns.

Lionesses have made their way with the cubs right on to the water's edge.

They have nowhere to go.

[Narrator] Dominant pride male Big Toe moves in to slow the buffalo advance.

[Greg] Big Toe has parked himself off, right in between the buffalo and the rest of the pride.

He's trying to hold his ground here.

Uh-oh!

[Narrator] But the buffalo have the upper hand.

[Greg] Here comes a bull.

You almost squashed Mathata!

Everyone's in the water.

[Narrator] Okavango lions are capable swimmers, but this is Mathata and the cubs' first flood.

[Greg] They're swimming.

Oh, my gosh.

[Narrator] They've never had to swim before.

[Greg] The cubs are panicking.

They can easily attract crocodiles.

We could lose one of these lions or cubs.

The lionesses are hesitating.

They don't want to get into deep water.

They're swimming after them.

Two of the mums are with the cubs.

Even a big lion like him is vulnerable to crocodiles.

They're still in deep water now.

Still deep, deep, deep, deep, deep, deep.

Yaw!

That was close!

They've made it across to this side of the channel.

Oh, that was too much.