Incredible footage of a lion fighting off a crocodile in a Botswanan river after it attacked his younger brother.

The video, filmed at Wilderness Safaris' King's Pool camp, shows the two big cats swimming across the Linyanti River, when suddenly a hungry crocodile attacks the smaller of the two.

Fortunately, the older lion fights back to protect his younger brother and helps him to safety.

One of the big cats then retreats to the shore they started from, while the other makes it to the other side.

The filmer, who was on safari at the time, told the story online, writing: "We found them [the lions] by the Linyanti river between Botswana and Namibia, and watched them drinking water.

"We thought they would come back out of the water but then we saw the younger one going back in."

"Our guide saw a crocodile on the right and we saw the older one look at the croc," she continued.

"Again we thought they would turn back but the younger one kept going in deeper.

"The older one hesitated and then followed him in.

"As they swim across the crocodile speeds up and while we all watched with our hearts in our mouths, the younger lion was attacked by the crocodile."

"The older one then attacks the crocodile and effectively saves his younger brother before going under the water; the younger one started swimming back and we thought the older one was gone, but then we saw him pull himself into the reeds - incredibly they both survived with no injuries!"

We were at Wilderness Safaris' King's Pool camp in Botswana, with our amazing guide ND tracking two young male lions we had seen in the area the day before. We found them by the Linyanti river between Botswana and Namibia, and watched them drinking water. Then the younger one stepped into the water and they both cautiously looked around, before turning back. We thought they would come back out of the water but then we saw the younger one going back in. Our guide saw a crocodile on the right and we saw the older one look at the croc. Again we thought they would turn back but the younger one kept going in deeper. The older one hesitated and then followed him in. As they swim across the crocodile speeds up and while we all watched with our hearts in our mouths, the younger lion was attacked by the crocodile. The older one then attacks the crocodile and effectively saves his younger brother before going under the water. The younger one started swimming back and we thought the older one was gone, but then we saw him pull himself into the reeds - incredibly they both survived with no injuries! The older brother was stuck on the Namibian side of the river for the rest of the day, while the younger one waited for a while, before finding a young lioness and mating with her. When the older brother came back later in the day, instead of challenging his younger brother for the lioness as would be expected, he waited nearby. An amazing wilderness experience we were privileged to observe and an incredible older brother!