PETALING JAYA: Any parent who has spent their weekend ferrying children to playdates might find a kindred spirit in the forests of Borneo. As it turns out, orangutan mothers also go out of their way to ensure their little ones have someone to play with.
And just like their human counterparts, these devoted mums sometimes sacrifice their own time and energy to keep the children entertained.
A recent study published in the journal Proceedings of the National Academy of Sciences has found that wild Bornean orangutan mothers deliberately adjust their movements through the forest to bring their young into contact with suitable playmates.
The findings, based on 15 years of observations in Indonesia's Central Kalimantan, offer a fascinating glimpse into the social lives of creatures generally regarded as the loners of the great ape world.
Unlike chimpanzees and gorillas, orangutans spend much of their lives alone. Mothers typically travel with their youngest offspring, who remain dependent on them for seven years or longer.
For youngsters eager to wrestle, chase and generally fool around, opportunities to meet other orangutan children can therefore be few and far between.
"Adults usually don't get very close to each other," explained Maria van Noordwijk of the Max Planck Institute of Animal Behavior, who led the fieldwork.
But the youngsters are another story. "They zoom toward each other, roughhousing, biting, grappling," she said. "Orangutan kids have a 'play button' that only mum can switch off when she decides it's time to move on."
A little detour for playtime
To understand how these encounters happened, researchers analysed approximately 32,600 hours of observations involving 31 mother-offspring pairs at the Tuanan Research Station.
They discovered that mothers with similarly aged youngsters tended to spend more time in overlapping areas of forest, giving their offspring opportunities to meet and play.
Interestingly, the mothers appeared to plan these encounters through their movements. They travelled towards neighbouring mothers' usual territories before playdates, then made their way back afterwards.
The pattern remained evident even after researchers accounted for factors such as family relationships and the availability of fruit.
"Mothers appear to match their kids with play partners that are physically and developmentally suitable," said lead author Odd Jacobson.
But arranging these jungle get-togethers came at a price: on days when their youngsters played, the mothers travelled farther and spent less time feeding.
And all that effort was often for a surprisingly brief reward - play occurred on only about 6% of observation days, with youngsters spending roughly 20 minutes playing together when such encounters happened. That's quite a journey for a short playdate!
More than child's play
Despite their solitary lifestyles, orangutans appear to maintain an awareness of their neighbours, including which mothers have youngsters of similar ages.
The researchers believe the apes may use their impressive spatial memory not just to locate food but also to seek out opportunities for their offspring to socialise.
The findings reveal another dimension of maternal care, suggesting that providing social experiences can be as important to these mothers as finding food and ensuring safety.
Whether the effort translates into measurable benefits later in the youngsters' lives remains uncertain. "We still don't know if the time and energy mothers spend arranging playdates give their young an advantage later in life," said study co-author Sri Suci Utami Atmoko of Indonesia's Universitas Nasional.
Nevertheless, the research provides a touching reminder that the demands of motherhood can extend well beyond our own species.