Sumatran Orangutans: Master Builders from Infancy
These baby primates start nest-building early, perfecting their skills over years
While human infants are still mastering basic motor skills at six months old, baby orangutans are already embarking on their journey to become expert engineers. These young primates engage in the complex task of building nests high in the tree canopy, showcasing an impressive blend of innate curiosity and learned behavior.
The Intricacies of Orangutan Nests
Orangutans construct elaborate sleeping platforms up to 20 meters (about four stories) above the ground every evening. These nests are intricate structures that can include woven elements, pillows, blankets, padding, and roofs to shield from rain. Unlike some animals, orangutans do not instinctively know how to build nests; they learn this skill through years of trial and error starting from a very young age.
Andrea Permana, a primatologist at the University of Warwick in England, says,
"A dangerous place to live when you’re so big and heavy… a poorly made nest can spell disaster.”
Long-Term Observational Study
To delve into how orangutans master nest-building, Andrea Permana and her team studied1 27 young Sumatran orangutans at the Suaq Balimbing monitoring station in Sumatra, Indonesia, over 13 years. This extensive observation allowed the researchers to map out the development of nest-building skills from infancy through to maturity.
Early Beginnings
From as early as six months old, baby orangutans start participating in nest-building activities, adding leaves and twigs to their mother’s nest. Young orangutans begin by constructing "day nests" — temporary platforms often used for lounging while foraging in fruit trees. Permana explains,
"Sometime before their first birthday, they’ve already started to try and bend branches around in a circle to try and make a nest foundation.
At this stage, young orangutans often struggle with the physical demands of nest-building. They will hang on branches with their body weight, trying to break and bend them, often with amusing results.
"They think they’ve made a circle and they let go and it just pings open. You can see they’re kind of surprised, like ‘Oh! It’s not as easy as it looks.’"
Intensive Practice Period
Between the ages of three and four, young orangutans enter a period of intensive nest-building practice. During this time, they refine their day nests and experiment with constructing night nests. One young male named Fredy built and destroyed 21 nests in a single day, showcasing the variability in effort, quality, and longevity. Permana notes,
"By about age five, young orangutans can build a respectable place to spend the night, usually constructing a nest a couple of meters above their mother’s in the same tree.”
Despite these advances, young orangutans often return to their mother’s nest for the night until they are fully weaned at around seven or eight years old.
Sinta, a 1-year-old Bornean orangutan, shows off her nest building skills. Sumatran orangutans (closely related to Bornean orangutans) start learning how to build nests as early as 6 months old, a new study shows.
Advanced Techniques
Once they have mastered the basic structure, young orangutans spend additional years perfecting comfort features like roofs and blankets. These sophisticated elements appear more frequently in nests built by adults, indicating a long learning process. Permana describes,
"Each night, every orangutan in Suaq that includes a pillow in its nest makes a special pillow-making vocalization. It’s like a human blowing a raspberry.”
Conservation Implications
Permana’s study represents the first detailed investigation into the development of nest-building in apes. Elizabeth Lonsdorf, a primatologist at Emory University in Atlanta, highlights the significance of this research, particularly for forest schools and rehabilitation centers that prepare orphaned orangutans for life in the wild by teaching them crucial survival skills like nest-building.
Conclusion
Understanding the complex and learned behavior of nest-building in orangutans provides valuable insights into their cognitive abilities and cultural practices. This knowledge is crucial for conservation efforts, ensuring that these critically endangered apes have the skills necessary to thrive in their natural habitats. The meticulous study of their developmental stages highlights the intricate balance between nature and nurture in the survival strategies of one of humanity's closest relatives.
Permana, A. L., Permana, J. J., Nellissen, L., Prasetyo, D., Wich, S. A., van Schaik, C. P., & Schuppli, C. (2024). The ontogeny of nest-building behaviour in Sumatran orang-utans, Pongo abelii. Animal Behaviour, 211, 53–67. https://doi.org/10.1016/j.anbehav.2024.02.018