Monkeys with more friends have better health and survival odds

Experts have found that wild monkeys who have more social ties also have a better chance of surviving the cold winter months. With more friends, the monkeys can form larger huddles to protect against hostile weather conditions and conserve energy.

According to the researchers, this is the first study is the first to demonstrate how social bonding can promote better resilience to environmental stress, or “fitness,” among animals.

The research was focused on wild Barbary macaques in Morocco. When the animals had a larger social circle of monkeys that engaged in grooming services together, they were able to form a bigger huddle at night.

This huddling strategy is a way of staying warm that is referred to as social thermoregulation, which helps the macaques maintain their body temperatures and spend less energy.

Dr. Bonaventura Majolo is a behavioral ecologist in the School of Psychology at the University of Lincoln.

“In several species, research has found that the most sociable individuals within a group tend to experience greater survival, longevity, reproductive output, and offspring survival,” explained Dr. Majolo.

“We know from previous studies of a number of different species that forming social bonds positively affects survival and reproduction, but exactly how this happens was not clear.”

The team observed the grooming and social lives of two wild groups of Barbary macaques. The experts documented the monkeys’ behavior both day and night, noting how many were huddled together at bedtime.

“Barbary macaques were an ideal species to examine because of the varying social relationships they have with their group companions, and the extreme weather conditions they experience, such as cold and snowy winters, and hot and dry summers,” said Dr. Majolo.

“We found that monkeys which were more sociable would huddle together during winter nights with their social partners, and that this led to the formation of larger huddles when it rained or the temperature dropped.”

The experts also recorded the air temperature and any precipitation events. In addition, they noted how much time the monkeys spent grooming, and whether the pair performing these services was of the same or opposite sex.

The study revealed that macaques who spent more time grooming together were more likely to huddle in the same groups at night. When it was cold, raining, or snowing, the monkeys were observed huddling in larger numbers.

“Social thermoregulation through huddling, communal nesting or communal roosting, is a very widespread behavior across a range of species, and this could therefore be a very widespread mechanism linking sociality with an evolutionary advantage,” explained study co-author Liz Campbell of the Moroccan Primate Conservation Foundation.

“In the ecological conditions of our study where Barbary macaques experience severe winter energy deficits, the benefits provided by social thermoregulation can explain why more social monkeys are more likely to survive winter.”

“In less extreme climates, more effective social thermoregulation could allow greater energetic investment in growth and reproduction, contributing to the greater longevity, reproductive output, and offspring survival experienced by more social individuals in other species.”

The research is published in the journal Scientific Reports.

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By Chrissy Sexton, Earth.com Staff Writer

Image Credit: Liz Campbell