Unravelling the mysteries of meerkat behaviour

Researchers at the University of Pretoria form part of the Kalahari Meerkat Project in the Northern Cape's Kuruman River Reserve, which has studied groups of wild meerkats for over 20 years.

Meerkats are fascinating animals that display intricate social behaviour. They live in groups of between four and 35 individuals and each group is governed by a dominant breeding pair that sires up to 90% of the surviving offspring. Other individuals in the group are subordinate to the dominant individual of the same sex. Subordinate mammals display high levels of co-operative behaviour, helping in pup raising and feeding. Despite their co-operative behaviour and assistance in things like pup-feeding and babysitting of the dominant pair's offspring, the dominant female is aggressive towards subordinates, causing high levels of stress among the subordinate females.

This project was started by Professor Tim Clutton-Brock, extraordinary Professor at UP and director of research of the Department of Zoology at the University of Cambridge. The KMP is a collaboration between the University of Cambridge, the University of Zurich and the UP Mammal Research Institute (MRI). It is managed in South Africa by Dr David Gaynor of the MRI and is focused on better understanding co-operative behaviour in these animals in order to gain greater insights into the social structures of mammals.

Recent studies within the project have focused on gaining novel insights into the maintenance of co-operative behaviour. UP researchers from the MRI, including Prof Nigel Bennett, and Professor André Ganswindt, Director of the MRI, in collaboration with other researchers in the KMP, simultaneously investigated multiple social, environmental and individual factors that affect stress levels of subordinate meerkats.

The study explored whether conflict between dominant and subordinate meerkats affect alloparental care by altering the levels of the stress hormone cortisol. This was assessed by looking at how the stress hormone cortisol affects assistance from subordinates with pup-feeding and babysitting, and what role food availability and other characteristics of the social group play in the levels of stress hormones in subordinate meerkats. By assessing stress levels in these different scenarios, more insight was gained into social conflicts and the cost of co-operation.

While both male and female subordinates endure higher levels of stress than dominant meerkats, it appears subordinate females display the highest levels of cortisol in their plasma, suggesting stronger competition between members of this sex. Cortisol is a hormone involved in the regulation of metabolism in cells and helps to handle stress within the body. It is part of the group of hormones known as glucocorticoids. Through observations and by measuring glucocorticoid levels, it was evident that dominant females exert a lot of aggression on other females. Findings show very high levels of aggression directed to subordinate females when the dominant female is pregnant. Previous studies conducted by the KMP suggest that this is because the subordinate pups compete with the pups of the dominant pair and subordinate females may kill these pups to favour the survival of their own. It appears that dominant females avoid this by evicting older subordinate females from the group before giving birth. In all these instances, it was found that subordinate females experienced escalated glucocorticoid levels in their systems.

Based on these findings, the KMP evaluated whether dominants direct aggression strategically to manipulate cortisol levels to increase the co-operative behaviour of subordinates. Their findings, however, do not show this to be the case. Although cortisol levels significantly affect participation in co-operative behaviour, it is not in a simple consistent way. Low levels of cortisol increased babysitting behaviour among subordinates of both sexes. For pup feeding, high levels of cortisol increased this behaviour in subordinate males, while low levels of cortisol receptor activity resulted in increased pup feeding among females. Dominant female meerkats did not adjust their levels of aggression to strategically enhance co-operative behaviour among subordinates. It appears that the function of aggression directed at subordinates is predominantly to stop them from breeding rather than to force them to co-operate.

By gaining greater insights into the social structures and behaviours of meerkats, Dr Gaynor and the KMP hope to improve future conservation practices of wildlife populations. The project continues to follow about 300 meerkats in the reserve on a daily basis, enabling the project to provide detailed information on how interaction between individuals lead to higher stress levels, and to measure the effect of different individual behaviours on the lifetime reproductive success.

Click on the gallery in the sidebar to view more from the Kalahari Meerkat Project.

Professor Tim Clutton-Brock, Dr David Gaynor, Prof Nigel Bennett & Professor Andre Ganswindt

November 8, 2017

  • Estimated Reading Time: 3 minutes

Researchers
  • Professor Nigel Bennett
    Professor Nigel Bennett has been at the University of Pretoria (UP) for 26 years. He holds a BSc (Hons) in Zoology, which he obtained at Bristol University in the UK, and undertook his PhD studies at the University of Cape Town.

    His research focus is animal physiology and behaviour using the African mole rat as his model animal. His work is directed primarily at studying the social regulation of reproduction in mole rats.

    Prof Bennett’s research record ranks him among the best researchers studying social regulation of reproduction in any group of mammals in the world. He has investigated cooperative breeding in mammals from a variety of perspectives. This multi-faceted approach has led to an integrated understanding of reproductive suppression in mole rats of a type that has not been achieved for any other taxa. His research has set the benchmark for our understanding of phylogenetic and ecological constraints that regulate reproductive success and social evolution in mammalian species.
    Prof Bennett has always been interested in why some organisms adopt a social lifestyle and others do not. As a young boy, he was fascinated by how wood ants worked for the common good of a queen. His interest in mole rats came about while he was an undergraduate at Bristol University, after he had read a seminal paper by scientist Jennifer Jarvis on cooperative breeding in the naked mole rat. Upon obtaining a position as a doctoral candidate, Prof Bennett wanted to see if this was a feature common to other African mole rats. He went on to study the Damaraland mole rat, and found it to have incredible social organisation similar to that of social insects and termites.

    Prof Bennett is now the world leader in African mole rat biology, particularly in reproductive physiology. A research milestone for him was discovering that breeding female naked mole rats orchestrate non-breeding males and females in the colony to exhibit high prolactin levels. This inhibits the release of hormones that stimulate the development of reproductive activities in the gonads, as evidenced by a lack of follicular development in ovaries and a reduction in numbers and motile sperm in testes. Prolactin also results in individuals exhibiting helping behaviour and cooperative care of the young.

    After nearly three decades of research on the reproduction of social African mole rats, Prof Bennett has not been able to determine how the breeding female actually inhibits reproduction in physiologically suppressed animals. This would be the magic bullet for potential contraception in humans.
    He leads a research group that strives to unravel how social evolution arose in African mole rats – solving this puzzle has important implications as to how social evolution arose among hominids. Essentially, it comes down to food acquisition and protection from predators, which is a central theme in social evolution in most mammalian groups.

    Two people influenced his career: Prof Brian Follett – who supervised Prof Bennett’s honours project and whose infectious enthusiasm for science and incredible lectures fired up Prof Bennett’s imagination – and Prof Jennifer Jarvis, who drove his passion to work on mole rats.

    In 2021, Prof Bennett was made an honorary member of the American Society of Mammalogists, a title bestowed on fewer than 100 luminaries in a century. He has been a visiting professor at the School of Chemical and Biological Sciences at the University of London’s Queen Mary College since 2005. More recently, he was a visiting professor at the Department of Zoology at King Saud University in Saudi Arabia.

    He is a member of the Academy of Science of South Africa, and a fellow of the Zoological Society of London, the Royal Society of South Africa and the African Academy of Sciences.

    Prof Bennett was awarded the UP Chancellor’s Medal for his research on three occasions and has received the Exceptional Academic Achiever Award for the past 14 years. He was also the recipient of the Zoological Society of Southern Africa’s gold medal and received the Havenga Prize for outstanding contributions to Life Sciences, awarded by the Academy of Science and Arts of South Africa. UP awarded him the University of Pretoria Commemorative Research Medal for being one of the top 100 scientists in 100 years of its existence.

    Prof Bennett has served as president of the Zoological Community of Southern Africa for two years. He is also editor-in-chief of the Journal of Zoology and a past editor of Proceedings of the Royal Society B: Biological Sciences. In 2013, he was the handling editor of Biology Letters, another Royal Society of London journal. He has published 433 papers in international peer-reviewed scientific journals, co-authored a specialist book published by Cambridge University Press and has penned 15 chapters in books.

    In his spare time, Prof Bennett travels to different countries in Africa to explore the wildlife. He particularly enjoys visiting the mountain gorillas in Rwanda and Uganda, and the eastern lowland gorillas of the Democratic Republic of the Congo. He is also an avid collector of African art and frequently visits markets to add to his collection.

    If he were not a researcher, Prof Bennett would have liked to have been a game warden in one of East Africa’s national parks to contribute to the protection of the incredible African fauna from poaching.

    ORCID ID: 0000-0001-9748-2947
    More from this Researcher
  • Professor André Ganswindt
    Professor André Ganswindt has been involved in research at the University of Pretoria (UP) for the past 15 years, since completing his PhD at the University of Münster in Germany.

    He says he chose to do research at a university in South Africa because the country has great potential and easy access to rich fauna, and that he chose UP because it supported his idea of establishing a specialised lab to support his field of expertise. To date, the Endocrine Research Laboratory is the only facility of its kind in Southern Africa. Prof Ganswindt regularly collaborates with colleagues in the Departments of Zoology and Entomology and Animal Science, as well as in the Health and Veterinary Science faculties.

    He studies behavioural endocrinology in mammals, reptiles and birds to address questions concerning regulative endocrine mechanisms, which in combination with other factors, like social or ecological changes, influence and control animal behaviour.

    Prof Ganswindt and his research group of postgraduate students are developing and validating non-invasive tools for monitoring reproductive function and responses to stressors in captive and free-ranging animals, and interlinking these approaches with studies on animal conservation, climate change, human-wildlife conflict, land transformation and urbanisation. It often leads to a cross-disciplinary approach of physiological-endocrine research, behavioural biology and wildlife ecology to improve the management and welfare of animals in zoological institutions as well as in the wild.

    This field of research contributes meaningfully to efforts to conserve wildlife, and in so doing, helps to protect ecological health on Earth. “Research, including mine, does not matter per se,” says Prof Ganswindt. “It only starts to matter if the findings contribute to a better understanding and (social) interaction with ourselves, our peer-group, related society and the world as a whole.”

    Prof Ganswindt says his research group has created a collaborative network of locally and globally recognised experts that focus on many aspects of mammal-oriented research, with several opportunities for basic and applied science, professional development, and relevant theoretical and practical training for undergraduate and postgraduate students.

    Having a large group of research students, about 10 PhD and 10 MSc students at any given time, means new research projects are continuously being initiated. Prof Ganswindt says a recent highlight was the inclusion of marine mammals in their research portfolio. Another recent PhD project non-invasively assessed trace elements to evaluate African savannah ecosystem health.

    The professor’s passion for his field of research stems from his fascination as a young child with the wildlife documentaries produced by Heinz Sielmann and marine conservation pioneer Jacques Cousteau. “I wanted to become a biologist ever since.”

    His academic role model is British evolutionary biologist and author Richard Dawkins. “In my opinion, he is an awesome thinker with fantastic discussion skills. Within UP, I would refer to Prof Nigel Bennett as my mentor, as he is not only a brilliant scientist, but also a very kind and supportive colleague.

    Prof Ganswindt advises school learners or undergraduates who are interested in his field to follow their heart if they know what they want to do. “Where there is will, there is a way. If you are not exactly sure what you want to do, try to create a list of what you don’t want – it narrows down the path.”

    As for recreation, he is interested in philosophy and is a keen CrossFitter.
    More from this Researcher

Related Gallery

Other Related Research

  • Story

    RE.SEARCH 7: Just Transitions

    This edition explores the theme of ‘Just Transitions’ which is generally characterised by ideas of sustainability and the greening of the economy, and supported by the ideas of resistance, rethinking and restructuring society for a better and more equitable future. As one of the most impactful producers of research in South Africa, UP has several specialised research teams that are on the...

  • Story

    Research shows there are more warm-bodied sharks than previously thought

    New research arising from a collaboration between scientists at the University of Pretoria (UP) and Trinity College Dublin has shown there are likely more warm-bodied sharks out there than previously thought.

  • Story

    UP researchers close in on the secret to aging

    The quest for immortality has long fascinated humans, and inspired countless tales – now, in two new studies published in the journals Nature and Science, University of Pretoria (UP) researchers, along with a team of global experts known as the Mammalian Methylation Consortium, are a step closer to unmasking the secret of aging in mammals, thus raising important questions – and answers.

Copyright © University of Pretoria 2024. All rights reserved.

Share