Friendships between male monkeys help alleviate stress, a new study has shown.
A study published in the journal PNAS looked at the strength of bonding among male Barbary macaques to assess the effect on their stress levels. They found that the stronger an individual’s social bonds with other males, the less stressed they became when faced with cold weather or aggression from other group members.
The team calculated stress by measuring the levels of stress hormones left behind in the monkeys’ droppings. The closeness of monkey friendships is shown by how often they sit together, eat together and groom each other.
In good weather or when they weren’t being pushed around by more dominant males, friendships did not have a strong effect on stress hormone levels. It was only when stressful factors increased that the benefits of these close bonds became clear.
The benefits of social bonding have been observed in female groups and mating pairs before, but it is unusual to see it in males. This is because male monkeys, along with many other animal species, are often competing with each other for status, territory, food and females.
The exact benefits to the monkeys of reduced stress levels are still to be confirmed, but it is known that high stress levels are not only harmful to mental health but physical health as well. This applies to humans as well as other primates. Stress can weaken your immune system, interrupt vital sleep patterns and slow down growth and healing. It can even shorten your lifespan.
According to Chris Young, a member of the team from Göttingen and Lincoln Universities who carried out the research: “In times of need keeping a few close companions, like we see in the Barbary macaques, is a very important thing.”