Moroccan monkeys huddle to brave the winter: Barbary macaques cozy up to their grooming partners on cold and snowy nights (and those with more friends have a better shot at survival)
- Monkeys with more social partners have a better shot at surviving the winter
- Huddling leaves the wild monkeys less exposed to environmental stresses
- It also allows them to save energy for growth and reproduction, experts say
When the wintry chill sets into the air, nothing quite beats the warmth of snuggling up to a loved one – or, in the case of Morocco’s wild Barbary macaques, many loved ones.
Researchers have found that monkeys with a larger number of social partners have a better shot at surviving the winter, as the groups are able to form huge huddles to keep warm.
The technique, called thermoregulation, leaves the monkeys less exposed to environmental stresses, allowing them to save more energy for growth and reproduction.
Researchers have found that monkeys with a larger number of social partners have a better shot at surviving the winter, as the groups are able to form huge huddles to keep warm
‘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,’ says Dr Bonaventura Majolo, a behavioural ecologist based in the School of Psychology at the University of Lincoln.
‘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.’
According to the researchers, this study is the first to show how the social bonding associated with huddling ties into the animals’ fitness.
The team observed the grooming behaviour and hierarchy of two wild groups in Morocco, observing their habits during the day and their preparations for night.
‘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 a cold and snowy winters, and hot and dry summers,’ Majolo says.
‘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 study showed that monkeys who spent more time grooming together were more likely to huddle.
And, when there was precipitation or especially low temperatures, they gathered in much larger groups.
According to the researchers, this study is the first to show how the social bonding associated with huddling ties into the animals’ fitness. The team observed the grooming behaviour and hierarchy of two wild groups in Morocco
DO MONKEYS RECOGNIZE FAMILIAR FACES?
Researchers have long thought that being able to recognize faces is innate in humans and other primates, and that something in our brains just knows how to do this from birth.
By 200 days of age, macaques form clusters of neurons responsible for recognizing faces in the superior temporal sulcus (red)
But a new brain imaging study suggests otherwise – macaques need to have been exposed to faces from a young age to be able to recognize faces.
To better understand the basis for facial recognition, Harvard Medical School researchers raised two groups of macaques.
The first one, the control group, had a typical upbringing, spending time in early infancy with their mothers and then with other juvenile macaques and human handlers.
The other groups of macaques grew up raised by humans who bottle-fed them, played with and cuddles them – while the humans worse welding masks.
This group of macaques didn’t see a face for the first year of their lives – human or otherwise.
Researchers have long thought that being able to recognize faces is innate in humans and other primates, and that something in our brains just knows how to do this from birth. But a new brain imaging study suggests otherwise
After they were raised in this way, both groups of macaques were put in social groups with fellow macaques and allowed to see both human and primate faces.
When both groups of macaques were 200 days old, the researchers used functional magnetic resonance imaging (fMRI) to look at brain images measuring the presence of facial recognition patches and other specialized areas, including those responsible for recognizing hands, objects, scenes and bodies.
The macaques who were raised seeing faces had consistent ‘recognition’ areas in their brains for each of the categories, but those who grew up never seeing faces had developed areas of the brain associated with all categories except faces.
‘Social thermoregulation through huddling, communal nesting or communal roosting, is a very widespread behaviour across a range of species and this could therefore be a very widespread mechanism linking sociality with an evolutionary advantage,’ said Liz Campbell, Programme Director at 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.’
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