Two lions make record-breaking swim for ‘female affection’

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Two lion brothers, including one with an amputated leg, were spotted making a record-breaking night swim through treacherous waters in Uganda’s Queen Elizabeth National Park.

Researchers believe that the nearly mile-long (1.6-kilometer) crossing of the crocodile-infested Kazinga Channel is the longest documented swim by lions.

And it’s another chapter in the story of Jacob, a resilient lion who has survived numerous life-threatening situations, including losing part of a leg to a poaching trap, during his 10 years in the park.

But why did Jacob and his brother, Tibu, cross the waterway connecting two lakes in the first place? They were likely in search of females after losing dangerous fights to another group of male lions — and to avoid humans while doing so, according to the researchers.

The scientists’ findings published Wednesday in the journal Ecology and Evolution.

“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,” said lead study author Dr. Alex Braczkowski, research fellow at Griffith University’s Centre for Planetary Health and Food Security in Australia, in a statement.

Jacob hangs out in a tree in the Ugandan park when he was younger. - Alex Braczkowski/Griffith University
Jacob hangs out in a tree in the Ugandan park when he was younger. - Alex Braczkowski/Griffith University

Braczkowski has been following Jacob’s story for eight years during his long-term study of African lions in Queen Elizabeth and other Ugandan national parks. As the scientific director of the Volcanoes Safaris Partnership Trust’s Kyambura Lion Monitoring Project, Braczkowski has worked with the Ugandan government since 2017 to record information about predator populations.

“Jacob has had the most incredible journey and really is a cat with nine lives,” Braczkowski said. “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.”

A dramatic river crossing

Braczkowski and his team, including field coordinators Orin Cornille and Bosco Atukwatse and camera operator Luke Ochse, wanted to capture videos of the brothers hunting and to find other lions by tracking Jacob and Tibu’s movements. Under the supervision of the Uganda Wildlife Authority, Ochse operated high-definition heat detection cameras on drones.

Jacob's leg was amputated after getting it caught in a steel poaching trap. - Alex Braczkowski/Griffith University
Jacob's leg was amputated after getting it caught in a steel poaching trap. - Alex Braczkowski/Griffith University

At the end of January, the team witnessed Jacob and Tibu enter into two vicious fights with other male lions within 48 hours. The other lions were trying to drive Jacob and Tibu out of their territory, and Jacob took the brunt of the damage, said Braczkowski and study coauthor Duan Biggs, associate professor and Olajos-Goslow Chair of Environmental Science and Policy at Northern Arizona University. Tibu led the other lions away from Jacob, and shortly after, they approached the channel.

The brothers made three attempts to cross the channel, turning back to shore during the first two tries. The video footage shows a heat signature trailing the brothers during one of their attempts, which may have been a crocodile.

While lions are fearsome predators, a Nile crocodile can easily kill a lion in the water, Braczkowski said. The crocodiles can weigh up to four times more than a male lion and have been observed killing lions as the big cats swam anywhere from 10 to a couple of hundred meters, according to the study authors.

With only brief stints of about 15 minutes between each attempt, the brothers were successful on their third try, taking about 45 minutes to cross the river. Jacob trailed his brother by 98 to 131 feet (30 to 40 meters), but both made it to the other side safely.

“The biggest surprise was the fact that they were getting into water with high densities of crocs and hippos,” Braczkowski said by email. “But finding females to breed with clearly is more important to the male lions than their own wellbeing or the potential risk of getting killed by crocs and hippos.”

The lions could have taken a small connecting bridge, but the researchers suspect that human foot traffic on the bridge deterred the brothers from choosing that path.

Shifting lion populations

Braczkowski has studied ratios of male to female lions, and his findings suggest that the lion population within the park is dropping.

“In healthy lion populations sex ratios are 2 females for every male, in Queen Elizabeth (it’s) the opposite,” he said. “Our latest lion census suggests lions in the park have declined by 50% in just 5 years.”

Other African reserves, such as the Maasai Mara or Serengeti, boast large lion populations, but they have measures that limit poaching and prevent lions from encroaching on livestock populations.

“In Queen (Elizabeth National Park) in contrast, you have 60,000 people living in the park, there are thousands of cows, and poaching rates are high,” Braczkowski said. “When these threats converge lions decline rapidly.”

Unlike other big cats, lions are social creatures, said Dr. Craig Packer, founder and director of the Lion Center at the University of Minnesota and Distinguished McKnight Professor of Ecology, Evolution and Behavior. Packer was not involved in the research but has dedicated decades to studying African lions and is the author of “The Lion: Behavior, Ecology, and Conservation of an Iconic Species.”

Previous research has shown that big cats such as lions and tigers can swim when necessary.

“They have these big plate-like feet, they’re strong, and they’re going to look for ladies somewhere,” Packer said after seeing the video. “There was terrific incentive to get across.”

Looking out for one another

Packer’s research has shown that when male lions stick together, they sire more cubs. And females in prides tend to give birth at the same time.

“So you get these cohorts of youngsters that grow up together, and they form a coalition,” Packer said. “Now if you’re a single male and you see a coalition of nine males, you would do more than just swim across the channel.”

Jacob (left) and Tibu stretch before going on an evening hunt. - Alex Braczkowski/Griffith University
Jacob (left) and Tibu stretch before going on an evening hunt. - Alex Braczkowski/Griffith University

Lions of the same gender are incredibly affectionate with each other, and they regard each other as lifelines, he said. Even groups of two or three males have a much better life expectancy, and solitary lions have a smaller chance of survival, Packer said.

So, it’s no surprise that Jacob and Tibu have stuck together, which has enabled them to survive. Multiple agencies have also stepped in to provide Jacob with veterinary assistance over the years, Braczkowski said.

But the biggest threat to lion populations is dwindling land, Packer said.

As the human population near wildlife reserves grows, more land is dedicated to agricultural spaces, reducing the areas where lions can roam and hunt for prey. Then, the lions cross over into populated areas and attack cattle.

Seeing Jacob and Tibu’s river crossing shows the lengths lions will go to for new living spaces and mates, Braczkowski said.

“These kinds of behaviors are emblematic of wildlife having to make increasingly risky decisions for resources and mates in human dominated landscapes,” Biggs said in an email. “If conservation is going to work for lions in places where people live, we need economic models that will support the communities that live closely to lions and suffer the brunt of their conflict with cattle.”

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