A troop of hamadryas baboons (Papio hamadryas) wakes from a night spent high on their cliff top home in north Africa and each morning they must leave the safety of the cliffs to go in search of food.
On this particular morning, they are stopped in their tracks as rival troop of baboons is heading their way. In the chaos of battle, males settle old scores and females are stolen.
Once revered by the ancient Egyptians, they are also known by the name 'sacred baboon'.
These monkeys live in a very complex society with no clear leader. Troops can have up to 400 members divided into dozens of small harems, each governed by a male.
Like all armies, strict discipline is essential if order is to be maintained.
Watch the moment when Sir David Attenborough and BBC filmmakers captured this gripping scene for the series Life.
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The Story of Life has been produced in collaboration with Sir David Attenborough, BBC Earth and ideas and innovation company AKQA.