Nav: Home

Social insecurity also stresses chimpanzees

April 05, 2019

A high social status has substantial health and fitness benefits for males and females of many social animal species, including humans. However, attaining and maintaining dominance often comes with elevated energetic costs. "To investigate costs associated with dominance acquisition and maintenance, we examined potential sources of energetic and psychosocial stressors that male chimpanzees might be exposed to on a daily basis, and particularly during periods when males compete intensively over dominance status and mating opportunities," says Anna Preis, first author of the study.

The authors found that urinary cortisol levels were higher in all males during unstable compared to stable dominance periods, whereas aggression rates showed the reversed pattern, with higher rates in stable periods. In contrast to a previous study in another chimpanzee population, dominance rank and urinary cortisol levels were not associated in either period. These findings indicate that status maintenance is not associated with elevated physiological stress for dominant Tai male chimpanzees, and suggest that status competition and the uncertainty of dominance relationships within the group exposes all males to psychosocial stress, despite lower rates of aggressive interactions. This supports a number of other studies showing that unpredictability in social relationships is particularly stressful in primates, - including in humans.

"Our study shows that open aggression was not the source of the high stress levels of males during periods of heightened male-male competition, but that males were affected by the social uncertainty induced by these competitive periods," says Preis. "We investigated two contexts that induce social instability, competition over status and competition over mating opportunities. For both contexts we found the same pattern: All males, irrespective of dominance rank, had higher stress levels during periods with high male-male competition, while aggression rates and intensities were higher in periods with low male-male competition."

Avoiding aggression

"One of our main findings is that male chimpanzees adjust competitive behaviors to context dependent conditions. When the risk of escalation was high, males avoided aggressive behaviors to diminish the risk of injury," says Roman Wittig, senior author of the study. "Chimpanzees are highly territorial and cooperatively defend their territories against intruders. Male chimpanzees might therefore avoid aggressive behavior when dominance relationship are unclear and unstable, as part of a conflict management strategy that allows them to cooperate as a group during such periods." Conflict management strategies are crucial for the maintenance of stable life in social groups. The study illustrates that wild chimpanzees contrast personal with group-level costs of aggression to manage their in-group conflicts.

"Our study is of interest for a wide research field. It shows that aggression rates are not always a good indicator of competition intensities and that in future studies avoidance of aggression and other non-aggressive forms of competitive behavior need to be considered, too," concludes Preis.
-end-


Max Planck Institute for Evolutionary Anthropology

Related Chimpanzees Articles:

Crops provide chimpanzees with more energy than wild foods
A University of Kent study has found that cultivated foods offer chimpanzees in West Africa more energetic benefits than wild foods available in the region.
The growing pains of orphan chimpanzees
Using long-term behavioral and hormonal data from wild chimpanzees in the Taï Forest, Côte d'Ivoire, researchers from the Taï Chimpanzee Project at the Max Planck Institute for Evolutionary Anthropology, have revealed that mothers may be shaping pre-adult growth and offspring muscle mass even without direct provisioning.
How humans and chimpanzees travel towards a goal in rainforests
How do human-unique ranging styles, like large home range and trail use, influence the way we travel to our goals?
Chimpanzees' working memory similar to ours
Working memory is central to our mental lives; we use it to add up the cost of our shopping or to remember the beginning of this sentence at its end.
Research identifies key driver for infanticide among chimpanzees
Study concludes that the sexual selection hypothesis was the main reason for the high rates of infanticide among a community of chimpanzees in Uganda.
Chimpanzees catch and eat crabs
Chimpanzees have a mainly vegetarian diet, but do occasionally eat meat.
Chimpanzees at the crossroads: adapt to living outside protected areas
Chimpanzees at the crossroads: how they adapt to living outside protected areas Research carried out into the impact of changes to chimpanzee habitats found they have adapted to human developments in a number of ways -- including learning how to cross roads safely and the best times to visit human habitats -- but their survival is still threatened.
Social insecurity also stresses chimpanzees
Researchers from the Max Planck Institute for Evolutionary Anthropology conducted behavioral observations and collected urine samples for cortisol analysis of male chimpanzees of the Tai National Park, Ivory Coast, during periods of intense male-male competition.
Sweeping census provides new population estimate for western chimpanzees
A sweeping new census published in the journal Environmental Research Letters estimates 52,800 western chimpanzees (Pan troglodytes verus) live in eight countries in western Africa, with most of them found outside of protected areas, some of which are threatened by intense development pressures.
Chimpanzees lose their behavioral and cultural diversity
Chimpanzees are well known for their extraordinary diversity of behaviors, with some behaviors also exhibiting cultural variation.
More Chimpanzees News and Chimpanzees Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.