Two lion siblings have set a new record for long-distance swimming, paddling across a treacherous stretch of river infested with crocodiles and hippos, on an epic adventure to find female mates.
The night-time swim across the Kazinga Channel in Uganda was captured by a H20T thermal camera mounted on a DJI Matrice 300 drone, and shows Jacob and Tibu testing the waters before committing to the cross, covering more than 1.3 km (0.8 miles), more than 10 times the distance of what was thought to be the longest observed lion paddle. African lions (Panthera leo) would normally cover around 10-100 m (33-330 ft).
Making the feat even more impressive is the fact that 10-year-old Jacob, well known to rangers and researchers in Queen Elizabeth National Park, only has three legs and is lucky to be alive.
“Jacob has had the most incredible journey and really is a cat with nine lives,” said Alexander Braczkowski from Griffith University in Australia. “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 swim wasn't smooth sailing, either. In the video, you can see the pair – known as a lion coalition – enter the water and then quickly return to the safety of the riverbank. On their second attempt, they make it about 80 m (260 ft), before changing their minds and swimming back to shore. A third try sees just one of the lions head out, but he appears to get spooked at around the same distance as the previous swim and paddles back towards his brother. Just as they look destined to be stuck on that one side of the channel, the pair commit to the crossing.
While the observation ends shortly before the lions make it safely back onto land, the researchers observed Jacob and Tibu near a gorge close to where they crossed the channel. It's an incredible feat for the siblings and in particular Jacob, whose three-legged paddle was somehow enough to evade the river's predators.
“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," said Braczkowski. “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 five years."
Because animal behavior is acutely guided by energy costs, the scientists believe Jacob and Tibu saw this tough journey as a life-or-death scenario in terms of finding a mate. With the park's lion population dwindling, and a recent defeat, the pair sized up the swim as their only option.
“It’s likely the brothers were looking for females,” said Braczkowski. “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.”
And while there's a small bridge that connects the two areas, the lions would have risked encountering humans on that route. Based on Jacob's previous brushes with death at the hands of poachers, it seemed he and his brother were more willing to take their chances with underwater Nile crocodiles (Crocodylis niloticus) and hippos (Hippopotamus amphibius).
Their epic long-distance swim also highlights another huge and underrated threat to species survival and biodiversity – population fragmentation. Male lions will disperse from their range if they can't find food, a mate or have too many territorial beefs with more dominant individuals. But when pockets of habitat become too fragmented, often through land-clearing and development, the distance for an animal to travel to reach another population becomes too great. Populations become isolated and then face a suite of issues, from resource competition to inbreeding, with numbers ultimately declining.
For Jacob and Tibu, luck was on their side, but Braczkowski – who has been undertaking a long-term study of the species and other predators in Ugandan national parks – noted that this perilous journey wouldn't have a happy ending for many lions.
“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,” he added.
The research was published in the journal Ecology and Evolution.
Source: Griffith University
