Dangerous predator forces lions to make 'life and death' swim across river

Ordinarily a 1.5 km record-breaking swim would be celebrated. But researchers have instead issued a warning.

A thermal drone followed the two lions as they crossed the Kazinga channel.
A thermal drone followed the two lions as they crossed the Kazinga channel in a record-breaking swim. Source: Alexander Braczkowski

While lions may be kings of the savannah, African rivers are ruled by crocodiles and hippopotamuses. So researchers were surprised to spot two large males make the dangerous choice to plunge into the water at night and swim for up to 1.5 kilometres.

Lions have been known to swim for a few metres, or even a few hundred metres in swampy environments. But drone footage captured by an Australian-led team in Uganda breaks all known records.

While ordinarily you’d expect to celebrate such an achievement, in this case of lion siblings Tibu and Jacob it’s sparked concern.

Dr Alexander Braczkowski, an expert in large mammals at Griffith University in Brisbane, believes the key question is what prompted them to make the decision to take such a huge risk, and spend over an hour swimming across to the other side.

“This behaviour is symptomatic of a larger problem in an increasingly human dominated world,” he told Yahoo News.

You can watch the lion's record-breaking swim below.

  • Hippos kill between 500 and 3,000 a year, but lions are responsible for only around 20 deaths.

  • Nile crocodiles are ambush predators and eat fish, reptiles, birds, and mammals.

  • Lions are polygamous and breed throughout the year.

Braczkowski has been working alongside Northern Arizona University, documenting how male lions are being forced to make more risky decisions in order to kind of fulfil their most basic life tasks. And in the case of the river swim, Tibu and Jacob needed to find a mate.

The problem the ageing duo have been facing is that the male to female sex ratio has been skewed. While a healthy lion population would have two females to every male, inside the Queen Elizabeth National Park the balance has been inverted, so competition for females is fierce.

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As a young lion, Jacob survived multiple attempts on his life and lost part of his leg in a snare. Source: Alexander Braczkowski
As a young lion, Jacob survived multiple attempts on his life and lost part of his leg in a snare. Source: Alexander Braczkowski

“Males are having to look for females, and they're willing to risk life and death crossing croc infested waters to do so,” Braczkowski said.

To cross to the other side of the Katunguru peninsula, Tibu and Jacob had two choices.

  1. A small road bridge with a big human presence.

  2. Swim across the Kazinga channel.

It’s not surprising they chose the latter. Their family was poisoned for lion body parts trade, and Jacob was caught in a poacher’s snare and later lost his leg in a separate attempted poaching incident.

Humans are increasingly the most dangerous predator in the 2,400 square kilometre park, and the population is estimated to now exceed 60,000.

Braczkowski believes Tibu and Jacob were well aware of the dangers of entering the river. In the video below you can see the lions made three crossing attempts. And during one, the pair are trailed by another animal.

“You can see they encounter something in the water — I think it’s either a hippo or crocodile. During one of the attempts when Jacob swims out to Tibu, it seems there's a splash in the water and he turns around,” Braczkowski said.

“I thought damn, this would be a crap way to go — getting eaten by a crocodile.”

Braczkowski said he’s followed countless animals during his career, but his relationship with Jacob is likely the “most intimate”.

Having reached the age of 10, he’s now in his twilight years, and despite multiple threats on his life, he’s survived.

“There’s probably never been anything I’ve been more obsessed with,” he said.

“I’ve known him since 2017. And to put it bluntly, I have no idea how so much can be thrown at one individual animal, and he just keeps saying, I'm not going to die.”

Long Distance Swimming by African Lions in Uganda has been published in the journal Ecology and Evolution.

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