2 lions made a mile-long swim across a crocodile-infested channel in search of mates. It's a sign of how desperate the animals are getting.

• Two lions in Uganda swam nearly a mile across a crocodile-infested channel seeking mates.
• Researchers said the swim is the longest on record for lions.

Two lions recently proved that there's no river wide enough to keep them from potential mates.

In February, the pair of brothers, Jacob and Tibu, swam for nearly a mile across a channel between two lakes in Uganda's Queen Elizabeth National Park.

They had to turn back several times because the water was likely full of crocodiles, according to Alexander Braczkowski, a conservation biologist with Griffith University who filmed the animals' epic swim.

Not only is this the longest swim for lions on record, but one of the brothers, Jacob, previously lost a leg when a poacher's trap caught his foot, making his feat all the more impressive.

"We didn't know lions could do this," Braczkowski, told Business Insider in an email.

Lions will wade or swim short distances, he said, "but nothing like what you see in the video."

The males were likely seeking out lionesses, Braczkowski and his fellow researchers reported in a recent paper in the peer-reviewed journal Ecology and Evolution.

Though the brothers made it to the channel's other side, it's unclear if they reached their goal of mating.

Jacob, the lion with three legs, is a survivor

Competition for mates is fierce because the lion population in the area has been cut in half in the past five years, Braczkowski said. Only 39 remain, with roughly two males for every female, New Scientist reported. In a healthy lion population, that ratio would be flipped.

An estimated 60,000 people live in the park, which has contributed to the decline in the animals' numbers.

"The main stressor is people," Craig Packer, founder and director of the University of Minnesota's Lion Center who was not involved in the research, told Business Insider. The lions hunt livestock and are killed in retaliation, he said.

Jacob is a reflection of the tension between humans and lions. Not only did he lose a limb, but poachers poisoned his family. And unrelated to humans, he also survived a buffalo goring.

"Jacob is a true symbol of the challenge lions face in Uganda but also their immense resilience," Bosco Atukwatse, a co-author of the paper, said.

A coalition of lions

Despite what Disney's "The Lion King" taught many of us about brotherly dynamics between the big cats, the close relationship between Jacob and Tibu is pretty typical. "Lions are the only social cat," Packer said.

Female lions live in prides, and they often give birth at the same time, Packer said. They raise their cubs together in a type of lion nursery, called a crèche.

Male cubs who grow up together, whether they're brothers or cousins, will stay together their whole lives in what's known as coalitions. "A coalition of two is not at all unusual," Packer said.

In fact, it's pretty necessary for their survival, Packer said. "It's scary being a male lion if you don't have a partner," he said. "And so you really need to look after your partner."

Just the roar of a second lion might be enough to chase off any competition for territory from other male lions.

And when it does come down to a fight, Jacob probably wouldn't be all that helpful to Tibu, Packer said, "but he's still better than nothing."