A new documentary, Relentless Enemies, tells the story of superlions marooned on an island:
“We discovered this tiny sandy island in the Okavango,” says Dereck. “It is extraordinary because it became totally isolated from the mainland 15 years ago when the course of the river changed, and a huge herd of buffalo and lions were trapped on a piece of land measuring 200 square kilometres.”Through this twist of geographical fate, these two ancient species are now engaged in a desperate battle of survival — watched by six bemused refugee wildebeest and a handful of similarly outnumbered warthogs.
Thus, the island has become a unique, ecological experiment. In order to exist without the customary spectrum of weaker African prey like zebra, giraffe and impala, the Duba lions have had to develop distinct strategies in order to trap the single available food source.
They have adapted to this challenge by hunting during the day under the baking African sun, swimming through deep rivers in the hunt for buffalo. This water-based training programme combined with a diet of protein-rich buffalo meat has led to the development of huge muscles, and these super-cats now dwarf other lions.
The island lions also use highly advanced psychology in their quest for food, predicting the course of the buffaloes’ daily trek by anticipating their need for water — then lying in wait at the precise spot along the river where the herd will eventually stop for refreshment.
In turn, the buffalo have responded to the threat by merging into a vast mega-herd of 1,200 beasts — five times the size of a normal group. They have also, at times, turned on the lions, killing isolated cubs.
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A subspecies is emerging which the experts have named the Duba swamp lion — as opposed to the jungle lion, the desert lion, or the lion of the mainland African plain. It is distinctive in appearance, with a bigger, thicker neck and an extra-strong chest. The lionesses are almost the same size as the male lions on the Botswana mainland.