Why did all-male armies become the norm? Fear of wives cheating

THE fact that prehistoric armies were made up almost exclusively of men has puzzled archaeologists for decades.

But now researchers have a theory – all-male armies formed because of a fear of sexual betrayal by their wives.

If all men did not go off to fight, those remaining behind would be able to mate with others’ partners, the study says.

Once a few more men were fighting than women, social pressure created a ‘sexual feedback loop’ that incentivised ever more to take part, researchers said.

The team at the University of St Andrews said the rarity of mixed-sex armies from prehistoric times to the present day was ‘puzzling’ because excluding women would effectively halve your fighting force.

Using a computer model, they found that once a few men had left for battle, the departure of each extra male created a greater incentive for others to take part – making them all less likely to be cuckolded. The study appears in the Proceedings of the Royal Society B journal.