A record-breaking swim by two lion brothers across a croc-infested African river has been documented.

A study, co-led by Griffith University and Northern Arizona University, highlights the two-male lion coalition undertaking a kilometre-long crossing the Kazinga Channel in Uganda at night.

One half of the lion brother duo is a 10-year-old local icon known as Jacob, who became famous for surviving a multitude of life-threatening incidents, one of which left him with an amputated leg.

Their risky swim river was captured using high-definition heat detection cameras on drones.

On the first of two attempts, they are seen being followed by a predator, possibly a crocodile, which causes them to split and head back to shore.

Previous reported swims by African lions have ranged from 10 to a couple of hundred metres, some of which resulted in deaths by crocodile attacks.

Dr Alexander Braczkowski, from Griffith's Centre for Planetary Health and Food Security, led the team that worked under supervision of the Uganda Wildlife Authority.



He said: "Jacob has had the most incredible journey and really is a cat with nine lives."

"I'd bet all my belongings that we are looking at Africa's most resilient lion: he has been gored by a buffalo, his family was poisoned for lion body part trade, he was caught in a poacher's snare, and finally lost his leg in another attempted poaching incident where he was caught in a steel trap."

"The fact that he and his brother Tibu have managed to survive as long as they have in a national park that has experienced significant human pressures and high poaching rates is a feat in itself – our science has shown this population has nearly halved in just 5 years. "

"His swim, across a channel filled with high densities of hippos and crocodiles, is a record-breaker and is a truly amazing show of resilience in the face of such risk."

Researchers are questioning why Jacob and Tibu risked the dangerous night swim in the first place.

Dr Braczkowski said: "It's likely the brothers were looking for females. Competition for lionesses in the park is fierce and they lost a fight for female affection in the hours leading up to the swim, so it's likely the duo mounted the risky journey to get to the females on the other side of the channel."

"There is a small connecting bridge to the other side but the presence of people was probably a deterrent for them."

Dr Braczkowski has been running a long-term study of African lions and other predators in Queen Elizabeth and several other Ugandan National Parks.



He adds this behavioural observation is a direct symptom of some of his previous research, highlighting skewed sex ratios in lion populations.

Dr Braczkowski said: "Jacob and Tibu's big swim is another important example that some of our most beloved wildlife species are having to make tough decisions just to find homes and mates in a human-dominated world."

The paper ‘Long distance swimming by African Lions in Uganda' has been published in Ecology and Evolution.