ASU study reveals 'work-life balance' for baboons

Research focuses on how male baboons split time between offspring, mating

June 2, 2023

Dozens of books and websites offer advice about how to achieve a satisfying work-life balance. People seek this advice because they have too much to do and too little time to do it.

New research published this week by Arizona State University researchers in iScience shows that humans are not the only creatures that have to balance conflicting demands — male olive baboons also make trade-offs between mating and parenting. Adult male baboon sitting on a rock holding a baby baboon. A male olive baboon caring for an infant. Photo courtesy Joan Silk/ASU Download Full Image

Male olive baboons devote a lot of time and energy to competing for access to sexually receptive females. They follow them around, try to exclude rival males and try to mate. The more time they spend near females around the time of conception, the more likely they are to sire infants.

But these same males also invest time and energy in relationships with particular nursing females, who are often the mothers of their offspring. These relationships, which researchers call “primary associations,” provide females and their offspring with protection and are the foundation of lasting ties between males and their offspring.

ASU researchers Caitlin Hawley, Sam Patterson and Joan Silk analyzed four years of data on two groups of wild olive baboons to find out whether males’ involvement in primary associations limited their involvement in competition over access to sexually receptive females. They were able to do this by measuring the number of primary associations that males were involved in at a given time, which varied from zero to five.

They discovered that males that were involved in more primary associations at a given time devoted less time to pursuing sexually receptive females than other males did. They also found that males that had more primary associates on a given day had a bit more difficulty juggling their relationships with their partners.

Although researchers have known for a long time that male baboons compete over access to females and that males also form close ties to nursing females, previous work had not investigated whether these activities were compatible.

baboons grooming

Baboons, shown grooming each other, are highly social. Photo courtesy Joan Silk/ASU

“Our results show that males can’t have it all; they have to make trade-offs,” said Silk, who is a research associate with the Institute of Human Origins and a Regents Professor with the School of Human Evolution and Social Change.

“Although baboons are very different than modern humans, the environments that baboons live in now is similar to the environment in which humans evolved. Our results may help us (with) understanding the dynamics (of) mating and parenting in the evolutionary history of our own species," said Hawley, the lead author of the paper and a graduate student with the School of Human Evolution and Social Change.

According to Patterson, a PhD graduate from ASU and postdoctoral researcher at New York University, the study also raises questions about the complex web of costs and benefits that parents and infants must navigate together.

“How do males, females and infants benefit from primary associations?" Patterson said. "Do these relationships help infant baboons grow faster or live longer?”

This work hopes to address these questions and more, and to gain new insight into the relative magnitude of the benefits males gain from mating and parenting.

In the study, there was some evidence that males that were involved in more primary associations also sired fewer infants than expected based on their dominance rank — though more data is needed to know whether this effect is robust.

Julie Russ

Assistant director, Institute of Human Origins


Study: A tough early life can have long-lasting effects

February 3, 2022

For humans, exposure to adversity early in life, and the negative social effects that may result, increase our susceptibility to illness and an early demise.

ASU primatologist Joan Silk, along with ASU doctoral graduate Sam Patterson and researcher Shirley Strum, turn to our primate cousins — female olive baboons — to understand the elemental behaviors that shape the processes connecting early life experiences to temperament and adult social outcomes. Mother and baby baboon. Mother and baby baboon. Photo courtesy Joan Silk

Their research, published this week in the Proceedings of the Royal Society B, demonstrates that female baboons who experience more adverse circumstances very early in life (i.e., during their first year of life) develop less benign interaction styles and weaker social bonds with others as adults.

“Baboons are an ideal study system for examining links between early life adversity, temperament and sociality,” said Silk, a Regents Professor in the School of Human Evolution and Social Change and research scientist with the Institute of Human Origins. “The females tend to remain in the same group throughout their lives and develop strong and supportive relationships with selected female partners.”

The analysis used behavioral data on 31 female olive baboons from three groups in Laikipia, Kenya. The researchers evaluated the links between early life adversity, interaction styles and female sociality. For baboons, early life adversity includes evaluations for environmental conditions in the year they were born, group size at birth, early loss of mother, the interval between successive births of the mother, and whether the individual was the first child of the mother.

Interaction styles among baboon females are measured as the tendency to utter quiet, low frequency calls — called grunts — as they approach another baboon. Grunts play an important role in negotiating social interactions because they function as honest signals of benign intent and are associated with lower levels of aggression and high levels of social connectedness.

baboons grooming

Baboon females with a baby grooming each other. Photo courtesy Joan Silk

An interesting result of this research is that early life adversity had a stronger effect on behaviors directed toward another female than behaviors initiated by the individual.

“Because adversity influenced their interaction style, it seems to impact social connectedness via multiple pathways, including physical condition and social attractiveness," said Patterson, who graduated with a PhD from ASU in 2021 and is now a postdoctoral scholar at New York University. "Females who are ‘nicer’ — by approaching another female with benign grunts — form stronger social ties and are more likely to be approached by others than those who are less ‘nice.’”

This work ties together threads from previous work that established links between early life experiences and adult sociality, temperament and sociality, and sociality and fitness in baboons. It is significant because it shows how unfavorable experiences early in life can have lasting influences on development and well-being throughout the life span.

The research article, “Early life adversity has long-term effects on sociality and interaction style in female baboons,” by Sam K. Patterson, Shirley C. Strum and Joan B. Silk, can be accessed online at

Julie Russ

Assistant director, Institute of Human Origins