Early Risers: Young Female Chimps Show Independence Through Nest-Building

As night falls in the dense forests of Uganda’s Kibale National Park, chimpanzees prepare for rest. High up in the canopy, they bend, weave, and twist branches into carefully structured nests. These arboreal beds, lined with leaves and twigs, provide a safe and comfortable place to sleep. But nest-building is not just about rest—it's also a skill that takes time to learn, requiring both strength and dexterity.

When it comes to making one's bed, there appears to a gap with chimps between the sexes: females, it seems, do it more often than males, and from a younger age. And that shows they're more independent, earlier in life. Credit: Iulia BăDescu

A new study published in the American Journal of Primatology has found that young female chimpanzees master this skill earlier than males, suggesting they develop independence at a younger age. The research, led by primatologist Iulia Bădescu of Université de Montréal, examined the nest-building habits of 72 young chimps in Kibale’s Ngogo community. The findings add to growing evidence that female chimps reach developmental milestones earlier than their male counterparts.

Learning to Build: A Chimp’s First Bed

Like all great apes, chimpanzees rely on nests for rest, security, and social interaction. Infants begin learning how to construct these structures within their first few years of life, initially watching their mothers and experimenting with branches. Over time, they refine their technique, eventually becoming proficient nest-builders by adolescence.

"Nest building also represents a type of tool use, since the chimps have to manipulate branches and other materials around them to construct their nest," said study co-author Tara Khayer, a biochemist at Université de Montréal. "Just like cracking nuts with stones or fishing for ants with sticks, nest building involves putting their environment to good use."

But while all young chimps must acquire this essential skill, the study found that females develop proficiency earlier than males.

A Gender Gap in Nest-Building

By tracking the behavior of young chimps over multiple years, researchers observed a clear pattern: females not only built nests more frequently but also started practicing at an earlier age than males. This suggests that female chimps gain independence from their mothers sooner than their male counterparts.

"The likelihood and overall rates of daytime nest building in wild infant chimpanzees varied with age and sex," Khayer explained. "Older and female infants were more likely to build nests, and build them more often, than younger and male infants."

Interestingly, once chimps started practicing, their rate of improvement was similar regardless of sex. This suggests that the gender difference lies not in ability, but in motivation or developmental priorities.

The Role of Nest-Building in Development

Nest-building isn’t just about rest—it serves different purposes at different life stages. For very young chimps, building a nest is often part of play, a way to explore and manipulate their environment. By the age of four, however, nest-building becomes more functional, providing a dedicated place for resting.

Nest building requires learning in early infancy and a threshold of physical development to manipulate tree branches. Credit: Iulia BăDescu

For young females, this skill may be particularly useful as they prepare to leave their birth group. In many chimpanzee communities, females migrate to new groups once they reach adolescence, meaning they must be capable of fending for themselves earlier than males, who often remain in their natal groups.

"Humans, too, sleep in beds," said Bădescu. "So there are interesting evolutionary implications. Studying how chimps learn to build nests from a very young age helps us better understand how all hominids, including us, develop and learn new skills."

What This Means for Understanding Chimpanzee Development

The findings from Kibale add to a growing body of research highlighting behavioral differences between young male and female chimpanzees. While males tend to engage in more rough-and-tumble social play, females often focus on skills that will help them navigate the challenges of adulthood.

This study also contributes to our understanding of primate cognition and the role of learned behaviors in survival. The ability to build a secure nest each night may seem like a simple task, but for a wild chimpanzee, it is essential. The earlier young females develop this skill, the sooner they can function independently—a trait that may offer an evolutionary advantage.

As research into chimpanzee behavior continues, studies like this help illuminate the complex ways in which primates, including humans, develop life skills and adapt to their environments.

Related Research

1. Lonsdorf, E. V., Markham, A. C., Heintz, M. R., Anderson, K. E., Ciuk, D. J., Goodall, J., & Murray, C. M. (2014). "Sex differences in wild chimpanzee behavior emerge during infancy." PLoS ONE, 9(6), e99099.

   • Examines early developmental differences between male and female chimps.

   • DOI: 10.1371/journal.pone.0099099

2. Fruth, B., & Hohmann, G. (1996). "Nest building behavior in wild bonobos (Pan paniscus): Implications for the evolution of sleep sites." American Journal of Primatology, 39(1), 19-34.

   • Investigates the role of nest-building in great ape evolution.

   • DOI: 10.1002/(SICI)1098-2345(1996)39:1<19::AID-AJP2>3.0.CO;2-7

3. Koops, K., McGrew, W. C., & Matsuzawa, T. (2012). "Chimpanzees and nests: A comparative study of nest-building in Mahale and Bossou." American Journal of Primatology, 74(4), 299-308.

   • Compares nest-building behavior across different chimpanzee populations.

   • DOI: 10.1002/ajp.22008

These studies add to a broader picture of how young primates learn and develop survival skills, offering insight into the evolution of human behavior and cognition.