Primate Behaviour and Cognition: Lockdown isolation making you feel more stressed? Listen to a chimpanzee’s advice

In third year module Primate Behaviour & Cognition, students study primate behaviour as a window into the function of behaviour and our own evolutionary history. This week we are featuring a blog post by Niamh McIntosh.
Niamh McIntosh
Niamh’s bio: I am a third-year student from Kent. I have very much enjoyed studying anthropology at Roehampton University and hope to pursue a career in the field of forensic anthropology.

Several studies have shown that for humans, social bonds and support are highly beneficial for our mental and physical health. But what about for our closest cousins in the animal kingdom? Do they also rely on friends during stressful times?

Roman Wittig and his colleagues (2016) studied wild chimpanzees from the Bundongo Forest in Uganda to see if their friendships affected stress levels. They collected urine samples to test the levels of a hormone called glucocorticoid, which is released from the renal gland, located above the kidneys, when an individual is under stress. Glucocorticoid hormone is an immuno-suppressant which means at high levels, it can put an individual at large risk for diseases and reduce life expectancy (Baxter and Rousseau 1979). It is therefore important to regulate the release of this hormone; however, stress disrupts this regulation, making it dangerous if experienced regularly (Marmot and Wilkinson 2005).

Urine was collected after three different scenarios: potentially life-threatening stressful events, everyday interactions with members of the group, or just resting. It was noted if they were with their pair bond during each event – this pair bond was determined based on certain behaviours displayed when there is a relationship, such as food sharing or grooming.  

Wittig et al. (2016) found that in all scenarios, individuals who had their pair bond to provide social support, had much lower glucocorticoid levels compared with those who did not. This shows that social bonds help regulate the release of glucocorticoid by stopping individuals from getting as stressed as they would without support. Friendships are therefore an evolutionary benefit that we share with chimpanzees – it is not unique to humans as many may have thought. Having friends increases life expectancy.

During lockdown we have been stripped of our social networks and support, leaving almost everybody feeling isolated (Marshall et al. 2020). Stress has also increased, with many finding they are struggling to deal with it (Marshall et al. 2020) due to the fact that there are no more meetings with friends after work to let off steam. Thanks to this article, we can hypothesise that the increased sense of struggling with stress felt by many could be partly due to our reduced social support from friends (Wittig et al. 2016). It is therefore important to maintain contact with social networks, through Zoom or socially distanced meetups, for our mental and physical health. If we continue to ignore the growing feelings of stress, it will start to have detrimental effects to our overall health and begin to cause major problems (Marmot and Wilkinson 2005).

Take a leaf out of a chimpanzee’s book and make dedicated time each day to focus on your friendships. We are lucky to have technology that makes it a lot easier to contact each other. It will not be the same as face-to-face meet ups, but the benefits are still there, you can still chat and lean on each other for support through this difficult time.

Make friends like a chimpanzee

Sick of that one friend who never returns the favours? Finding you are no longer trusting them? According to chimpanzees you should cut ties and run, for a friend you can’t trust is no friend at all.

A recent study has found that chimpanzees trust their friends more than their non-friends (Engelmann and Hermann 2016). Just as with humans, the relationship between bonded individuals includes an emotional investment: trust.

Jan M. Engelmann and her colleague Esther Herrmann, from the Max Planck Institute for Evolutionary Anthropology, are behind this fascinating insight into non-human relationships (Engelmann and Hermann 2016). They studied fifteen chimpanzees from Sweetwaters Chimpanzee Sanctuary, Kenya, over the course of five months. The chimpanzees took part in a trust game, where they had two options to choose: 1) pulling the trust rope which delivers the food to the opposite individual first, who is then expected to reciprocate, or 2) pulling the no-trust rope that just delivers less tasty food directly. In other words, the game requires the chimp to trust that the individual opposite them would return the favour of pulling the rope, thus providing delicious goodness.

Engelmann and Herrmann observed that a significant number of chimps were more likely to pull the trust rope for their friend than non-friend members of the group. This provided strong evidence that chimpanzees felt trust for an individual they have formed a social bond with, and therefore have emotional investments in relationships very similar to our own.

Animals clearly have highly developed social intelligence that effects their lives to a greater extent than many realise. With humans, several studies have found that quality of friendships impact our lives so significantly that they affect our mortality and therefore our life expectancy (Hot-Lunstard et al. 2007). Could this be the same for other animals?

The excuse that animals are not as intelligent and emotionally complex as us has led to a dangerous fashion of mistreating animals and providing a poor quality of life. Studies like this one are helping to break these assumptions, educating people that we are not unique in our intelligence. For example, domestic species such as goats that are used primarily for production are often seen as simple (Nawroth et al. 2018); however, it has been found they can read and process negative and positive facial expressions on humans (Nawroth et al. 2018), a trait showing that they potentially have a more complex emotional intelligence than once thought. All of this evidence is proving that  animals’ lives are just as valuable as ours and should be treated as such.

Have you tried the latest spider monkey diet?

No, I do not mean a diet where you eat spider monkeys. I mean that by looking at the diets of spider monkeys, scientists have a potential solution to humans’ mounting obesity problem.

Annika Felton and her colleagues from the Ferner School of Environment and Society studied the diets of Peruvian spider monkeys to try to understand what drives their food selection. They observed each individual continuously for twenty-four hours and noted which foods were eaten. Samples of each food were collected, and the nutrients calculated to decipher which types of foods the monkeys were feasting on (Felton et al. 2009).

The authors discovered that spider monkeys regulated their protein intake using their diet. Despite food sources fluctuating through seasons, the protein level remained the same, meaning they were selecting foods for their protein. For other nutrients such as carbohydrates and fats, it depended on what food was in season and readily available to them as to how much they would consume. Spider monkeys therefore prioritise their protein consumption over fatty foods.

So, what does this mean for humans? Spider monkeys and humans share a common ancestor, meaning we are distantly related, but our diets are very different. Previous studies have stated that humans are evolved to favour fatty high energy foods, due to our ancestors being more active for hunting and longer time in between meals (Rozin 1997). From this study we can hypothesise that we began replacing our protein diet with fatty foods, perhaps because that is what was more readily available to us. It gives us a new way to try and tackle the mounting obesity problem (Trowell 2017). Rather than obsessively thinking about what foods we are eating, which makes us want to eat more (Rozin 1997), we could change what is readily available to us., making it so we only have access to healthy foods and more protein, which would help by lessening the temptation to eat foods high in carbohydrates and fats. That way there is no need to restrict on how much you are eating, as it would all be healthy.

Will you try the new spider monkey diet? Nothing else has worked so far, fight the power of these big sugary corporations and do something healthy for yourself.

Finding you are struggling in class more than your peers? Baboons may hold the answer as to why

Children are unique from each other, but they all share the capacity to learn from those around them. So why do some children do better than others?

A study by AJ Carter and his colleagues (2014) offers some insights.  The team looked at wild baboons in Tsoabis Par, Namibia, to see if their different personalities affected the way individuals learned from their environment and have found that personality type affects the way that baboons learn information.

The baboons were separated based on how bold or shy each individual’s personality was, and how anxious and calm they were. An unfamiliar food was then placed in their regularly used trails and they were observed to see how they reacted to the new stimulus.

Researchers found that the bolder personalities were more willing to interact with the food and learn for themselves if it were edible. Shyer individuals would stay back from the unfamiliar food and instead observe the bolder individuals before deciding to approach and eat it. Calmer individuals were more likely to handle food compared to anxious ones, but when these aspects were combined with boldness and shyness, they did not make a difference, meaning that the main aspects of personality that influenced the way a baboon would learn were boldness and shyness.

How does this help humans with classroom behaviour? Well, it shows that lumping everyone together and making them listen to someone talk, is not going to benefit all students with the way they learn (Fisher 2005). If personality affects the way baboons learn, then it is surely going to affect the way humans learn, especially as we are all so different from one another and have unique personalities (Buss 1991). Perhaps those students whose grade is failing is not due to a lack of intelligence or enthusiasm but the fact that their classroom is not teaching in a way that benefits their personality and best method of learning. Of course, as we are all so different it would be difficult to cater for everyone, but it is clearly important to try, as everyone deserves to reach their full potential. Make sure each lesson has a mixture of observing and participating, use the new technologies that are constantly expanding the way of teaching (Fisher 2005).

Give students some time in lessons where they can choose what they feel works best for them, instead of dictating how they should learn. Those bold trouble-makers in the class may just need coaching a different way.



Baxter, J D., Rousseau, G G., 1979. Glucocorticoid Hormone Action: An Overview. Europe PMC. Vol.12, pp. 1-24.

Buss M. D., 1991. Evolutionary Personality Psychology. Annual Review Psychology. Vol. 42, pp. 459-491.

Carter A. J., Marshall H. H., Heinsohn R., Cowlishaw G., 2014. Personality Predicts the Propensity for Social Learning in a Wild Primate. PeerJ. Pp. 1-22.

Engelmann, J M., Herrmann, E., 2016. Chimpanzees Trust Their Friends. Current Biology. Vol. 26, pp. 252-256.

Felton M. A., Felton F., Raubenheimer D., Simpson J. S., Foley J. W., Wood T. J., Wallis R. I., Lindenmayer B. D., 2009. Behavioural Ecology. Vol. 20 (4), pp. 685-690.

Fisher R., 2005. Teaching Children to Learn. Nelson Thornes. Pp. 175.

Holt-Lunstard, J., Uchino, N B., Smith, T W., Hicks, A., 2007. On the Importance of Relationship Quality: The Impact of Ambivalence in Friendships on Cardiovascular Functioning. Annals of Behavioural Medicine. Vol. 33, 3, pp. 278-290.

Marmot, M., Wilkinson, R., 2005. Social Determinants of Health. OUP Oxford. Pp. 376. 

Marshall, L., Bibby, J., Abbs, I., 2020. Emerging Evidence on COVID-19’S Impact on Mental Health and Health Inequalities. The Health Foundation. 

Nawroth, C., Albuquerque, N., Savalli, C., Single, M-S., McElligot, A G., 2018. Goats Prefer Positive Human Emotional Facial Expressions. Royal Society Open Science. Vol. 5, pp. 1-8.

 Rozin P., 1997. Why We Eat What We Eat, and Why We Worry about it. Bulletin. Vol. 50 (5), pp. 26-48.

Trowell H., 2017. Obesity in The Western World. Plant Foods for Man. Pp. 157-168.

Wittig, R M., Crockford, C., Weltring, A., Langergraber, E K., Deschner, T., Zuberbühler., 2016. Social Support Reduces Stress Hormone Levels in Wild Chimpanzees Across Stressful Events and Everyday Affiliations. Nature Communications. Pp. 1-8.

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