© Getty Images Men need nights out with the lads, scientists say
It is the news no long-suffering wife wanted to hear: scientists have proved that every man needs a good night out with his friends.
According to the research, male bonding is more likely to lower a man's stress levels than a night out with his partner, or time spent with the family.
The study – bound to be wheeled out as an excuse by men across the country – found males suffer less anxiety when out in a group.
Scientists from Germany's University of Gottingen studied groups of Barbary macaques, a type of ape which exhibits remarkably human-like social behaviour.
Levels of male stress hormone soared when male macaques were with their partner or other family members. But when they were in a group of other males, they were more much more relaxed.
The researchers even discovered stress-related illnesses only seemed to occur among females or couples.
Males also look after each other, the study for the journal PNAS noted. While men may do this by watching each other's backs, for monkeys this means picking insects and fleas out of each other's fur.
Christopher Young of the university's Primate Social Evolution Group said: "If male primates live in multimale groups they usually fight fiercely over access to females, but males can develop friendly relationships with a few group mates.
"Male macaques form social bonds similar to human friendships that buffer them against day-to-day stressors."