Master Internships

Please contact the appropriate supervisor in Animal Behaviour and Cognition if you are interested in the following projects as part of a masters study. Please let us know the following when you contact us:

• Which project you are interested in, and why: please detail your motivation.
• Your relevant academic experience (for example, have you completed a course in animal behaviour / animal ecology or an allied discipline? Such experience is normally a prerequisite for beginning an internship).
• Which course you are currently doing, and where you are studying.
• How long an internship you are looking for.
• When you would like to start and finish, and your flexibility regarding these dates.

Students from outside Utrecht should inform us of any special requirements made by their home university and must ensure that academic credit earned here is transferable. Please check with your home university that it is possible for you to do an internship here before you get in touch with us.

Projects categorised by topic:

• Primate social cognition
• Animal welfare (zoo/lifestock)
• Diverse topics: Bonobo's, chimpanzees, great tits, a.o.

Primate social cognition: in the Netherlands and elsewhere

1. Anti predator responses of captive primates to acoustic and visual predator models

Many primate species possess specialised anti-predator techniques that enable them to cope with their predators and control mortality risks.  Rapid and accurate predator recognition lies at the core of these techniques, and natural selection should favour mechanisms that facilitate this process. Three basic processes may be at work in helping individuals to recognize and respond appropriately to predators. Firstly, prey animals may possess an inherited predisposition to recognize and respond adaptively to certain animals with anti-predator behaviour. Secondly, predator-naïve animals may not accurately recognise a predator on their first encounter, but they may be equipped with a particularly efficient learning mechanism, which allows them to learn the features of different predator types with a small number of trials, either by experiencing a direct interaction with the predator or by witnessing the anti-predator behaviour of others. Thirdly, it is conceivable that individuals possess some inherited predator knowledge, but that this knowledge is incomplete and requires experience before appropriate anti-predator behaviour is possible. For example, in some animal species accurate predator recognition in the visual domain appears to be less experience-dependent than recognition in the acoustic domain: in this case animals may lose a specific response evoked by a particular predator type, while retaining more general antipredator behavior evoked by archetypical cues that are shared by a class of predator species (e.g. predator shape). In this study, we will subject captive individuals to the sights and sounds of different predator types and determine whether their species-specific vocal and behavioural anti predator responses to both the sights and sounds have been retained under relaxed selection pressures over several generations. 

Start: flexible

Contact:  Dr. Anne Marijke Schel (a.m.schel@uu.nl)

2. Budongo (Uganda): Is vocal behaviour of Guereza colobus monkeys affected by predator pressures

This study will look into Guereza colobus monkeys’ dawn chorusing behaviour and investigates whether or not the dilution effect may explain the vocal behaviour of these animals. A 2010 study on guereza colobus monkeys showed that these monkeys reliably responded to playbacks of conspecific dawn chorusing, even if this meant they were the only two males calling in the area.  This has been linked to a male rivalry function in this species, allowing individual males (who lead a group of females) to indicate their fighting ability. Eight years later, in 2018, guerezas in the same study area were very reluctant to start calling back in response to playbacks of conspecific male dawn chorusing. Circumstantially, in the approximately 10 years since the previous playback experiments had been conducted, chimpanzee hunting pressures have risen substantially. To find out if the monkeys have adapted their calling behaviour to this increased predation pressure, this study will use playback experiments to investigate whether males that are reluctant to respond to played back dawn choruses by themselves are more likely to start calling when multiple males are already calling in the area (either in response to the playback or playback induced). This would still show their fighting ability to neighbouring males, but at the same time they may ‘mask’ their exact location for eavesdropping predators and may become less vulnerable for predator attacks.
Contact: Study ideally starting in March and conducted at Budongo Conservation Field Station (BCFS) in Uganda- if allowed by UU and BCFS Covid guidelines. Dr. Anne Marijke Schel (a.m.schel@uu.nl)

3. Measuring affective states in animals subjected to acoustic and visual predator models

Primates often produce alarm calls in response to different predator types. The acoustic properties of such calls may differ (either gradually or discretely). This difference has been related to the context in which these calls are produced (e.g. the type of predator or its speed of attack) and may be  associated to the affective states experienced by the callers at the moment of call production. In this study, we will subject captive primates to the visual and vocal presence of predator models that are either presented from far away or closeby and aim to capture their vocal and affective anti predator responses. This is done by recording their vocalisations and changes in body temperature and relating the call specific vocal parameters and accompanying changes in temperature to the current literature on animals’ affective behaviour.

Start: flexible

Contact: Dr. Anne Marijke Schel (a.m.schel@uu.nl)

4. Laterality of hand use during the initiation of play

Several primate species communicate with their conspecifics through the use of body signals. These include body postures and body movements, as well as particular movements of hands, feet, limbs and head. If these signals are produced flexibly with an intention to change the behaviour of the recipient, these signals are called gestures. Thus, gestures can be used flexibly to facilitate efficient communication between signallers and recipients, and some researchers have suggested that gestural communication may lie at the base of our own extraordinary capacity for language. One line of evidence supporting these claims comes from studies on manual laterality during gesture use. These studies show that in some primate species a right hand preference during the production of communicative gestures is found, in combination with strong neuronal firing activity during such (manual) gesture production in a particular neuroanatomical area of the left cerebral hemisphere that has been linked to speech production in humans (a homologue of Broca’s area). Thus, it appears that the left brain hemisphere is in control during such ‘formal’ communicative events, leading to a right hand preference for such formal communication. During play, however, gestures from a variety of ‘formal’ communicative contexts are used,  but are clearly produced in a less formal communicative context: this may lead to a less strong hand preference for producing gestures during play. This research will explore whether the handedness of communication during play differs from that in other settings.
Contact:  Start October 2022- January 2023. Dr. Anne Marijke Schel (a.m.schel@uu.nl)

5. Regulation of primate relationships in macaques: the role of tolerance and cooperation

Group life is only possible when benefits outweigh the costs. However, group members may have different needs and compete with each other. Animals navigate this social environment by forming social relationships with their group members. Traditionally, aggression and the related dominance hierarchy has received most attention. However, it is becoming clear that also friendly relationships are important. While friendly relationships result in fitness benefits, the underlying mechanisms are not clear.
In this research we explore how macaque friendly relationships relate to tolerance in food tasks. This research combines an observational and experimental (by giving enrichment) approach.
Researcher: Prof. dr. Liesbeth Sterck (email: e.h.m.sterck@uu.nl)
Application: at least one month before start student research (a researcher may not be able to place a student in such short notice)
Requirements: course in 'Socioecology'; course in statistics

6. Is yawning in chimpanzees related to stress or vigilance?

Project duration – 8 to 9 months (incl. 5 – 6 months of rigorous fieldwork in Burgers’ Zoo, Arnhem)
Yawning is an evolutionarily old behaviour that is widespread among vertebrates. However, there is still much debate on its function. The hypothesis that it serves to increase oxygen uptake, although still pervasive, has been proven false long ago. On a proximate level there is, however, convincing evidence that yawning serves a thermoregulatory function, i.e. it cools the brain back to homeostasis. But the ultimate reason why animals do that remains unknown. Yawning has been linked to arousal levels and stress. Alternatively, it is thought that by cooling the brain, yawning induces vigilance. Evidence for the vigilance hypothesis is still lacking, but there are some studies that indirectly support it.
The aim of the proposed project is to further investigate both the stress and the vigilance hypothesis and we do this by looking at post-conflict yawning in a group of captive chimpanzees and by investigating the effects of reconciliation and consolation on those post-conflict yawning rates. Conflicts induce stress and the possibility of renewed aggression may require vigilance. Reconciliation and consolation influence these patterns differently. This study requires a lot of observational hours to get as many conflicts as possible, as well as the required matched controls.
We’re looking for a highly motivated, contentious and patient student that wants to do that extra mile. Experience with behavioural observations of a social species is preferred.
Supervisor: Dr. Jorg J.M. Massen (j.j.m.massen@uu.nl)

7. Female family business in Japanese macaques

Japanese macaques (M. fuscata) live in complex and large multi-male multi-female societies with a strict dominance hierarchy. Females represent the social core of the group with long-lasting bonds with their female kin. The social rank of females is inherited from their mothers. However, studies indicate that females benefit from social bonds with non-kin. Therefore, we aim to study the occurrence of these non-kin social relationships of females, how they are formed, which females form them and how they influence the matrilineal- and individual female rank.

While contributing to this project, you will:

• Collect & analyse behavioural data in a population of approx. 180 Japanese macaques.
• Observe this beautiful species in semi-free ranging conditions.

Project details:

•  Location: Field work is done at the Affenberg Research Station in Landskron, Austria.
• Duration: End of September until December OR January 2025 until May 2025 (Exact duration and startingh time can be discussed).
• Housing: Provided with affordable costs.
• Teamwork: You will be part of a collaborative team of interdisciplinary researchers including geneticists, primatologists and other biology students.

We are looking for a motivated team player who is able to work patiently with animals, does not mind working outside for longer durations despite weather conditions, can think independently and is flexible in research plans.

For further information, feel free to contact:

Jorg Massen - j.j.m.massen@uu.nl    or   Roy Hammer     -     roy.hammer@univie.ac.at

8. Something’s gotta give! Social tolerance in monkey societies

Social tolerance refers to the ability to be in each other’s social space without pronounced aggression. As such, social tolerance has been identified as an important phenomenon with the potential to facilitate behaviours with immediate benefits, like cooperation and social learning. Yet, how can we measure social tolerance? And is social tolerance a species-specific trait or does it vary from group to group? In this project, we will experimentally test the extent of social tolerance across multiple groups of macaques. Here, macaques are an especially interesting family of primates to investigate given the established classification of their social tolerance levels (e.g., egalitarian VS despotic) based on species-wide generalizations. Method. In each group (n=8-12), we will employ a co-feeding experiment consisting of a predetermined arena of limited and depletable food resources from which group members are free to feed. We will measure how many group members can simultaneously benefit from the food resource and compare these numbers across groups to assess potential group differences. Furthermore, we will use focal sampling techniques to measure dyadic tolerance levels within the experimental arena (e.g., in terms of socio-positive behaviours, food sharing, and displacement). Lastly, we will apply social network analyses to obtain insights into metrics of social tolerance beyond the dyads. We seek highly motivated student(s) to conduct simple experiments with rhesus and long-tailed macaques at the BPRC, Rijswijk. The student will have the exciting chance to acquire knowledge on social behaviour in macaques and social network analyses in order to challenge the established idea that macaques can a priori be grouped at their species level to assume their group-specific climates of social tolerance.
Contact: Edwin van Leeuwen: e.j.c.vanleeuwen@uu.nl

9. Food sharing in bonobos and chimpanzees

Food sharing in the Pan species (chimpanzees and bonobos) has been studied for its potential to assess whether prosociality (benefitting others) is a derived trait in the human lineage or rather an evolutionarily older proclivity shared with humans’ closest living relatives. Whereas research from wild populations indicates that chimpanzees share meat after successful hunts, not much is known about their food sharing tendencies in general, and the extent to which group-specific dynamics may preclude species generalizations. In the current study, we will investigate if groups of bonobos and chimpanzees share food with their group members and, if so, what factors may drive their prosocial giving. Method. We will conduct a food sharing experiment in which one bag filled with carrots, or carrots and apples (TBD), will be placed in the ape group after which the ensuing dynamics will be monitored by means of focal follow procedures with cameras. We will conduct 8-10 sessions per group. The focus will be on scoring the frequencies and types of food sharing, including the dynamics of the identities of the food owner and potential food recipient. The scoring of these elements will be done from video recording afterwards, but during the recording we will narrate the dynamics to facilitate coding afterwards. We seek highly motivated students (2) to execute these experiments, possibly in the Chimfunshi Wildlife Orphanage (Zambia). The PI is an experienced researcher and member of staff at CWO and might join you to familiarize with the setup. The student(s) will be challenged to work remotely in a very safe sanctuary setting with good communication channels. The student(s) will have to cover the costs for this experience abroad themselves. For more information, please contact the PI.
Contact: Edwin van Leeuwen: e.j.c.vanleeuwen@uu.nl

10. Group differences in Social Learning strategies and efficiency in rhesus macaques.

Social learning is the ability to learn from others. It is useful to acquire new behaviors cheaply and efficiently and is a capital step in the establishment of group-specific cultural behaviors. Despite the paramount role of social learning in the fitness of individuals, there is a gap in empirical studies about how the social structure and social climate of a group influence the individuals’ capacities to learn from each other, as well as the social learning strategies employed (“who to learn from”).

Combining behavioral observations and tasks with a social learning box and using state of the art statistical analyses (Network Based Diffusion Analysis), we will determine the social learning capacities and strategies employed by the monkeys. On a more individual level, we will also look at the characteristics of the first task solvers (the innovators).

We seek a highly motivated student to perform behavioral tasks and to code the subsequent videos, to make behavioral observations (scan sampling), and social network analyses. The internship will take place at the Biomedical Primate Research Center (BPRC), in Rijswijk, NL.

Project start date: flexible, preferably October/November 2024.

Contact: Eythan Cousin, e.cousin@uu.nl

11. Social transmission of food preference during introduction in rhesus macaques, a case of conformity or local adaptation?

Culture is a pervasive aspect of human life, influencing the way we live, socialize, or even eat. But is culture as important in other primate species? To understand the prevalence, transmission, and maintenance of arbitrary cultural traits (“norms”), we propose to perform a food preference experiment in groups of Rhesus macaques. The aim of this experiment is to understand the transmission of food preference during a critical and stressful moment of an individual’s life: immigration. Newly introduced males need to be accepted in the group, and blending in by acquiring the habits of the group could be a way to facilitate the integration. We will therefore create an eating tradition by triggering group-level food aversions in rhesus macaque groups during the mating season (winter). We will then assess if a newly introduced male in the group picks up this food preference, and even change its own pre-established food preference to match the one of their new group (therefore showcasing a potential conformist bias). This protocol will be performed following several male introductions.

We seek a highly motivated student to perform behavioral observations (scan sampling), simple behavioral tasks and code the subsequent videos, as well as statistical analyses. The internship will take place at the Biomedical Primate Research Center (BPRC), in Rijswijk, NL.

Project start date: September/October 2024

Contact: Eythan Cousin, e.cousin@uu.nl

12. The establishment of cultural norms: social transmission of food preference during infancy in rhesus macaques.

Culture is a pervasive aspect of human life, influencing the way we live, socialize, or even eat. But is culture as important in other primate species? To understand the prevalence, transmission, and maintenance of arbitrary cultural traits (“norms”), we propose to perform a food preference experiment in different groups of Rhesus macaques. The aim of this experiment is to understand the transmission of food preference during infancy. We will create eating traditions by triggering group-level food aversions in Rhesus macaques at the end of mating season and at the beginning of birth season (February-May). We will then assess if newly born infants in the subsequent birth season will acquire the food preference from their mothers or from other conspecifics, leading to the development and establishment of arbitrary group preferences, using state-of-the-art statistical analyses (Network Based Diffusion Analyses and Experience Weighted Attraction models). We will also analyze the maintenance of such a food preference overtime.

We seek a highly motivated student to perform behavioral observations (scan sampling), to videotape simple behavioral tasks and code the subsequent videos, as well as to perform statistical and social network analyses. The internship will take place at the Biomedical Primate Research Center (BPRC), in Rijswijk, NL.

Project start date: Spring 2025 Contact: Eythan Cousin, e.cousin@uu.nl

13. Grooming pattern transmission in rhesus macaques - learning a complex social skill.

Grooming is one of the foundations of non-human primate societies: it strengthens, maintains, and repairs the relationships between individuals. It can be used as a currency, and has direct health benefits. But grooming is not an easy task. The

individuals need to learn from a young age when to approach a conspecific, when to perform or accept a grooming present, and how to actually groom the hair of others efficiently and “nicely”. How do macaques acquire these skills? By performing careful behavioral observations with a detailed grooming ethogram, we aim to answer this question and understand if the grooming patterns (which body parts to groom, and what gestures to use) are passed on through generations from mothers to infants, are similar in all individuals from the same species (pointing toward a genetic basis for the skill) or are a group-specific characteristic. We also aim to disentangle if the way individuals groom specific sensible parts, like the face or genitals, is linked to the relationship quality.

The student will video tape and analyze the grooming bouts of several groups of Rhesus macaques, focusing on groups that seem to already have specific patterns of grooming.

We seek a highly motivated and patient student, interested in pursuing careful observations of this specific and meaningful behavior. The internship will take place at the Biomedical Primate Research Center (BPRC), in Rijswijk, NL.

Project start date: Flexible

Contact: Eythan Cousin, e.cousin@uu.nl

14. Infant’s emotional expression. How does the lost of the mother or the arrival of a new-born sibling affect the behaviour and physiology of infant rhesus macaques

Mother-infant relationships is the first and most important attachment in humans’ and animals’ life. Although this attachment is essential for physical and emotional well-being, this attachment also comes with negative consequences over time. Animals’ studies show how mother’s rejection and unavailability affects the infant development as well as it is seen as a stressful situation for the infant. One example is when the infant experiences maternal loss or disturbance during its early developmental stage, it is deprived of its primary caretaker, leaving the infant vulnerable to physical dangers and social stress. Such early maternal loss therefore can lead to detrimental effects on the physical and emotional development of the infant’s life, resulting in short and long-term negative behavioural and physiological consequences of mother-infant conflict. Another example is the transition to siblinghood (TTS). TTS is a stressful and emotional event for an older sibling that occurs after the sibling’s birth, and it comes along with the “weaning conflict”. In point of fact, Behringer et al (2022) found higher urinary cortisol in these animals after the sibling birth and these higher cortisol levels were not reduce for seven months in bonobos. In this study, we aim to observe how the birth of a sibling affects the emotional processes of the older siblings (1-2 years old infants) in a different primate, in rhesus macaques. We aim to study their social behaviour as well as their vocal behaviour.

About the project: All the data has been collected in the previous years, we need a student to analyse the behaviour and vocalizations collected during focal observations. Experience in behavioural analyses is appreciated but not required.

Contact: Paula Escriche Chova (p.escrichechova@uu.nl)

start: October 2024

15. Effects of the mother-infant condition in the HPA axis in infant rhesus macaques. Is the HPA axis affected by the mother-infant disturbance?

Humans as well as animals respond to stress by activating a wide range of behaviours and physiological responses. The main physiological mechanism activated during stress is the hypothalamic-pituitary-adrenal axis (HPA), being cortisol the ultimate output of the HPA axis. Stressful situations, therefore, produces an increase in peripheral cortisol in humans and nonhuman primates. Although cortisol has been studied in a wide range of scenarios, there is little knowledge to how significant life-history event during development affects the long-term activity of the HPA axis in a natural setting (no experimental). One factor that alters the HPA axis during development is the mother-infant interactions. Mothers act as a social buffer for the infants, and experimental or natural disruptions in mother-infant relationship experiences seen as a prolonged stressful situation can produce a significant increase in cortisol concentrations.

In our study, we plan to observe how mother-infant early challenges affects the functionality of infant’s HPA axis and as consequence, the infants’ cortisol levels. We want to investigate two significant life-history events, the natural and spontaneous mother’s death during the first/second year of life and the birth of a sibling during the first year of life.

About the internship: The goal of this study is to analyze cortisol in hair (method used to determine chronic stress). Note: we required a student with lab experience and, if possible, experience with Elisa kits.

Contact: Paula Escriche Chova (p.escrichechova@uu.nl)

Start: October 2024

16. Group-service in rhesus macaques: prosociality and social learning

Group living animals compete and cooperate with their group members. Yet while competition may be easily understood, elucidating the evolutionary mechanism of cooperation has proven to be challenging despite theoretical and empirical explanations. This is particularly the case when animals provide others with a benefit, while they do not gain themselves. Especi8ally animals with a clear and despotic dominance hierarchy, like rhesus macaques, may find it difficult to provide others. To test this hypothesis, we will test the monkeys with a group service paradigm in their social group, where the individual that pulls the apparatus cannot obtain food itself, but does provide group members. We will also study how they operate the apparatus and whether they learn individual or socially. Several groups will be tested.
Project duration: 6 - 8 months (incl. 5 – 6 months of observations/experiments at BPRC, Rijswijk, NL)
Project start date: flexible
Supervisors: Liesbeth Sterck (e.h.m.sterck@uu.nl) and dr. Jorg JM Massen (j.j.m.massen@uu.nl)
Requirements: We are looking for a highly motivated students for the project.

17. The primate gut-brain axis: Is gut microbiome composition associated with stress-related behaviors in zoo-housed bonobos?

The microbes living in our gut are known to play an important role in regulating our physical and mental health. However, recent literature also emphasizes the potentially major role of the gut microbiome in the regulation of brain function and behavior. Gut microbes are crucial for the proper development and regulation of behavior and cognition, giving rise to a connection between the brain and the gut, known as the gut-brain-axis. Conversely, the social behavior of the host itself will directly influence the composition of the gut microbiome, indicating the axis is bidirectional. To date, very little is known about the gut-brain axis in animals, especially in non-human primates. Therefore, the aim of this study is to characterize the bonobo gut microbiome and to investigate if gut microbiome composition is associated with stress-related behaviors in a large multi-zoo sample of bonobos. The student will aid in laboratory analysis of the fecal samples starting September 2022 (KULeuven, Belgium) and work with existing behavioral datasets to link to the microbiome profiles. Behavioral data collection would not be required, but could be included for Planckendael bonobos if there is interest, rather than doing laboratory analysis of fecal samples.

• Laboratory analysis to produce microbiome profiles at KULeuven starting September (date can change slightly depending on completion of fecal sampling by then).
• Analysis of individual microbiome profiles to inform 11 zoological institutes on their bonobos in comparison to the other zoos that participated in the project. 
• If behavioral data collection: Uninterrupted availability for 3 consecutive months to collect data. Your own laptop is required to install observer software and fast and blind typing is crucial for successful completion of this project.

Contact: Jonas Torfs jonas.torfs@uantwerpen.be and Nicky Staes nickystaes2@gmail.com

18. Behavioral responses to long calls of zoo-housed Bornean orang-utans (Pongo pygmaeus)

Project duration – 9 months (major) or 6 months (minor).
Location – Apenheul Primate Park (Apeldoorn, The Netherlands).
Summary – Orang-utan males are known for their large cheekpads and impressive long calls. The long call has multiple functions, such as deterring other males, attracting females (e.g. Mitra Setia & van Schaik, 2007), and communicating travel direction (van Schaik et al., 2013). Possibly, the long call contains information about health, identity and dominance of an individual (Askew & Morrogh-Bernard, 2016). Importantly, not only flanged males produce long calls. Unflanged males that are transitioning towards flanged males already start producing proto-long calls. However, these calls do not have the same intensity yet as those of fully developed males.
In this project, we will study whether female orang-utans respond differently to the calls of flanged males or unflanged males. We will do this using a playback setup, where we play short fragments of long calls, and videorecord the behavioral responses of the orang-utans before, during and after the sound stimulus onset. Apart from this, you will be expected to record behaviour of the orang-utans outside of the playback sessions. By observing the behaviour of the orang-utans during the study period and after the study period, we hope to be able to investigate how an experiment like this affects the welfare of the orang-utans over a longer time period.
NOTE: at the start of the project we will first pilot the playback setup with the orang-utans. If the zoo thinks that the playbacks are too stressful for them, we might have to switch to an observation-only design. However, it is unlikely that this will happen.
Project start date – Flexible, preferably as soon as possible. Supervisors – Tom Roth (Animal Behaviour & Cognition, UU, t.s.roth@uu.nl).
Requirements – I am looking for a motivated student with good communication skills, because this project will also involve contact with animal caretakers. Previous experience with observing primates and working with BORIS are a plus, but not essential.

19. Primate psychiatry – an ethological approach

What? We are interested whether mental disorders occur in non-human primates. Using ethological methods of observation we aim to study whether we can identify syndromes of harmful behaviors.

Our research questions are: Can we recognize syndromes of harmful behavior – i.e. mental disorders - that are measurable with an ethogram? And finally, how do afflicted individuals respond to pharmacological and non-pharmacological interventions? And can we eventually obtain enough empirical data to start building diagnostic tools for non-human primates, and evidence based treatment plans for such diagnosed mental illnesses.

Why? Over the last decades a lot of effort has been put into increasing the welfare of captive animals, ranging from increasing the size of enclosures, providing better and more diverse diets, to providing safe spots and enrichment. Nevertheless, primates, among others, are known to demonstrate behavioral disorders in captivity, particularly those individuals that have experienced some sort of trauma. The resulting abnormal, and sometimes even harmful, behavior may cause great suffering, yet also suffers from a lack of scientific understanding. We expect the symptoms of these disorders to partly overlap with the symptoms of mental disorders in humans. We would like to describe clinical experiences and perform scientific research using both diagnostic and observational techniques to contribute to the body of research available to clinicians and keepers.

Where? At the Stichting Aap primate rescue center in Almere, the Netherlands

How? Our study design is observational. We make use of ethological methods to understand behavior. The design is bottom-up, which means that students will study the behavior of specific animals without any assumptions about their mental well-being (blind for any diagnostics so far), and using statistical methods aimed to find patterns that may help us categorizing them, after which quality checks will be performed in discussion with care takers and veterinarians.

Who? We are a team of behavioral biologists and psychiatrists that aim to understand more of the behavioral disorders in primates, preferably in a complex social, i.e., naturalistic, environment.

When? Flexible

Duration Flexible: 4-12 months

Contact information Tieme Dolstra, MD (t.o.dolstra@uu.nl); Dr. J.J.M. Massen (j.j.m.massen@uu.nl)

20. Macaque youtube: attentional preferences for agonistic interactions of neighbours and strangers in rhesus macaques (Macaca mulatta)

One specific effect related to group membership is the “dear enemy” or “nasty neighbor” effect (Christensen & Radford 2018). These terms refer to the observation that animals respond either more strongly to strangers (dear enemy), or respond more strongly to neighbors (nasty neighbor). In this study, we will study whether group membership (neighbors vs. strangers) modulates preference for affective stimuli in rhesus macaques. More specifically, we want to use macaques as a model species to investigate whether a well-know socioecological negative bias towards neighbors vs. strangers is present in rhesus macaques, and whether it translates into a specific bias for negative-valence stimuli of neighbors. To study this, we will use a previously validated paradigm (Watson et al. 2011) that allows macaques free access to a touchscreen. By selecting a specific symbol that is associated with a specific video category, they can control the presentation of either a neutral (sitting) or a negative (conflict/submission) scene depicting a neighbor or a stranger. We expect that rhesus macaques will show a stronger bias towards negative scenes over neutral scenes in neighbors.

Location: Biomedical Primate Research Center (Rijswijk, The Netherlands)

Activities: stimuli preparation, touchscreen experiments, video analysis

Start date: flexible Supervisor: Tom Roth (t.s.roth@uu.nl) & Jorg Massen (j.j.m.massen@uu.nl)

21. Effect of visitor presence on zoo-housed orang-utan welfare

Visitors can be both enriching and stressful for zoo-housed animals. However, this effect might strongly depend on the species being studied. In this project, you will focus on the welfare of zoo-housed Bornean orang-utans (Pongo pygmaeus) in Apenheul Primate Park (Apeldoorn, The Netherlands). Because Apenheul is closed to visitors in the winter, it is possible to investigate

differences in behaviour between the period with and without visitors. Behaviours that can be investigated range from space use and locomotion behaviour to use of food enrichment. In addition, there might be an option to also participate in running cognitive experiments (voluntary participation) with the orang-utans (eye-tracking/touchscreen), but we are still discussing the options to run such studies with the zoo.

Location: Apenheul Primate Park (Apeldoorn, The Netherlands)

Activities: behavioural observations, performing cognitive experiments (maybe)

Start date: flexible (observations), but if we get permission to perform cognitive experiments ideally in november. Supervisor: Tom Roth (t.s.roth@uu.nl)

22. Touchscreens as cognitive enrichment in duo-housed macaques?

Providing animals with more choice and control over their environment may improve their wellbeing. One potentially interesting approach entails providing digital cognitive enrichment, for example via touchscreens. The aim of this study is to investigate whether digital cognitive enrichment has a positive effect on the welfare of macaques in paired housing. Previous studies on the use of digital cognitive enrichment in various primate species often demonstrate positive effects. However, these studies often concern case studies, which limits their generalizability. This project aims to test whether digital cognitive enrichment has a positive effect on animal welfare in duo-housed macaques. To investigate this, you will combine a touchscreen task (in which individuals can choose what kind of video they want to see) with behavioral observations. These observations will allow you to test whether the animals make use of the touchscreens and whether you observe any differences in behaviour (social, movement, self-directed) between touchscreen sessions and control sessions. Hopefully, this will tell us more about the enrichment value of touchscreens.

Location: Biomedical Primate Research Center (Rijswijk, The Netherlands)

Activities: touchscreen experiments, behavioural observations (from video)

Start date: flexible Supervisor: Tom Roth (t.s.roth@uu.nl) & Dian Zijlmans (d.g.m.zijlmans@uu.nl)

23. Nuts about nuts: precursors of nut-cracking in chimpanzees (Pan troglodytes)

– 1 student (Minor project, data collection from September to October 2024)

Nut-cracking is a widely known example of tool use in chimpanzees (Pan troglodytes). However, it is not a ubiquitous behavior – only certain groups have been reported to crack nuts. Environmental or genetic factors fail to explain why that is, as neighboring groups of chimpanzees evolving in similar landscapes contrast in having developed this food processing technique. Furthermore, studies have reported numerous groups-specific methods of nut-cracking, all pointing out towards the fact that this behavior is rarely invented and requires social transmission to persist. In conjunction, this holds nut-cracking as a striking example of culture in non-human animals. However, conditions leading to the emergence of nut-cracking are opaque. Multiple parameters may be conducive to this behavior (e.g., opportunity, necessity, motivations), and it is possible that its emergence would be facilitated by pre-existing and transferable knowledge in “hard” food processing, but studies have yet to investigate these in a large-scale comparative setting. To address this gap, this project aims at providing optimal conditions for the spontaneous emergence of nut-cracking in multiple sanctuary-based chimpanzee groups. It consists in cataloguing group and individual-specific techniques in processing hard-shelled fruits, before introducing palm nuts as a new food source in their daily diet. The student would then analyze whether pre-existing knowledge in processing of fruits facilitates the emergence of new nut cracking techniques.

Research will be conducted at Chimfunshi Wildlife Orphanage Trust in Zambia

24. “And” or “then”? Can chimpanzees (Pan troglodytes) acquire arbitrary sequences of actions?

– 1 student (Major project, data collection from March to June 2025)

Performing numerous behaviors in sequence requires a relatively complex level of cognitive capacities, as they involve memorizing, ordering, and understanding cause and effect relationships in a string of actions leading to resources obtention. Numerous species can perform such sequence of actions for targeted goal, such as our closest evolutionary relative the chimpanzee (Pan troglodytes) – think of termite fishing or nut cracking. However, it has been questioned whether they would be able to do so if the order of action leading to the resource was arbitrary, instead of causal. This “uniquely” human sequential aspect could be at the root of complex behavioral expressions where rules are customary and arbitrary, such as language. In the present experiment, we are aiming to test what information chimpanzees can extract from a token exchange task where the rewards provided rely on an arbitrary sequence of action. Chimpanzees would be tasked to exchange colored balls where the reward they obtain is dependent on the sequence of balls they exchange. Students would monitor results, and investigate strategies switches in chimpanzees throughout running the experiment – do they pick colors at random (no understanding of internal rules), do they prefer color diversity (lacking arbitrary order understanding but picking on actions that have more chance of being rewarded), or do they harness parts or all elements of the sequence (thus understanding a partial or complete sequence of action with an arbitrary order)?

Research will be conducted at Chimfunshi Wildlife Orphanage Trust in Zambia

25. Better than more: can Pan species cumulatively improve their performance at a token exchange task

– 1 student (Minor project, data collection from November to December 2024)

Capacities to repeatedly accumulate and socially sustain beneficial modifications to a behavioral ensemble therefore improving overall performances has often been deemed a uniquely human trait. Dubbed cumulative cultural evolution (CCE), this trait has since then been claimed to exist in other species (e.g., homing pigeons, humpback whales, Japanese macaques) and across varied behavioral categories (e.g., migration, songs, tool use). However, whether such phenomenon can be expressed in the Pan species, our closest evolutionary relatives, remains unanswered. The aim of this project would be to evaluate Pan species capacities in improving and refining performances in a token exchange task. The apes would be provided with colored balls they can exchange for a given reward, which depends on two different parameters – the number of balls exchanged in the time allocated, and the diversity of colors exchanged. Prolonged testing would allow getting an insight in modalities of strategy switching in great ape species: do individuals appear to use other’s experience as baseline to improve their own performances? Do social conditions foster performances improvement? How differently and/or similar do the groups of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) perform?

Research will be conducted at Leipzig Zoo

Bird Internships

26. Social structure of Rüppell's vultures

Project duration – 6 - 8 months (incl. 5 – 6 months of observations/experiments at Avifauna, Alphen a/d Rijn NL or Blijdorp, Rotterdam)

Summary -

Traditionally studies on social cognition have focusses on primates, rendering specific hypotheses about the evolution of (social) intelligence. Yet, to study the generalizability of these hypotheses, it is paramount to also test them in other taxa. Recent studies have started to also look at birds, but are restricted to two groups of species that are known for their intelligence, i.e. corvids and parrots. Little is known about other species of birds. A group of birds that is largely overlooked are vultures, specifically so because recent analyses revealed they have relatively (to body size) big brains. Therefore, in this project we want to investigate social intelligence of vultures, and specifically of Rüppell’s vultures, which along with some other vulture species, is a social species.

To set the groundwork we are firstly interested to describe the social structure of these vultures and to infer from these data whether they have for example a linear hierarchy, have knowledge about such a hierarchy, show demarcated social relationships (e.g. friendships) etc. As the project is relatively explorative, we specifically welcome students with own ideas.

The project involves observations of one group of Rüppell’s vultures in their natural group rendering ecological relevance. One student will observe the vultures in Avifauna, where the vultures will have recently moved from a relatively small aviary to a large new aviary. In their new enclosure, the Rüppell’s vulture is the focus species but more species may be introduced over time. As data was collected before the move, here it is also possible to investigate the influence of this large change on vulture (social) behaviour. The other student will work with the Rüppell’s vultures in Blijdorp, where they are living in a mixed-species exhibit together with another social vulture, the white-backed vulture, as well as white-headed vultures, hooded vultures, Marabou storks, secretary birds and more. In addition to investigating their social structure, the interaction between the Rüppell’s vulture and the closely-related but much smaller white-backed vulture could also be of interest. Data from both groups can be shared between the two students depending on the research question.

We are looking for Two highly motivated students for this exciting research. Students will learn behavioural sampling techniques, vulture behaviour, data coding, statistical analyses, and scientific writing.

Project start date – Flexible. Supervisors – dr. Jorg JM Massen (j.j.m.massen@uu.nl) and Eva SJ van Dijk (e.s.j.vandijk@uu.nl). Contact us with a short letter of motivation and CV.

27. The influence of UV-light on king penguin courtship behaviour and mate choice

Animals that experience biparental care often go through courtship rituals before they form a pairbond. During these rituals, individuals perform behavioural displays sometimes aided by specialized morphological structures (e.g. coloured ornaments). An example of such a courtship ritual is that of the king penguin (Aptenodytes patagonicus). Besides their extensive behavioural courtship repertoire, they also possess UV-reflecting ornaments that might reflect their mate quality. However, captive populations do not always have an enclosure that is enriched with UV-light. Therefore, the main aim of this study is to investigate the courtship behaviour of king penguins in an enclosure with UV-light and compare their behaviour with data from a previous season. This will help to understand how important UV-light is for mate choice in king penguins.

Location: Dierentuin Blijdorp (Rotterdam, The Netherlands)

Activities: behavioural observations (focal & scan), picture analysis (maybe)

Start date: flexible, but at latest february 2025 Supervisor: Tom Roth (t.s.roth@uu.nl)

28. What explains individual and species differences in innovative ability?

The environment around us is constantly changing, and as humans we are capable of adapting ourselves to these changes, finding new ways to overcome difficulties that we encounter and using what we already know. However, we are not the only species capable of doing this.  There are many examples of how animals can solve problems they encounter and use this knowledge in new ways. A key factor for this is innovation ability. This ability, however, varies between species, populations, and even individuals within populations. Although studies on innovative ability have shown the importance for adaptation and fitness, it is still largely unclear why some individuals are capable of coming up with extraordinary solutions to problems whereas others are not.
In this project we investigate which key factors make some animals more innovative than others. We use blue tits, marsh tits and great tits as our study species both in the wild and in captivity.
Work can include: fieldwork, behavioural measures in captivity during summer, autumn and winter, Innovation behaviour in spring; Starting date: any date
Supervision contact details: Kees van Oers (k.vanoers@nioo.knaw.nl); Utku Urhan (u.urhan@nioo.knaw.nl)

29. Habitat matching or local adaptation: how does habitat quality drive variation in cognitive traits

The environment is changing rapidly, and it is essential for animals to behaviourally adapt to these changes. In order to adjust their behaviour adaptively they need to collect, retain and use information from their  changing environment, processes referred to as cognition. While cognition is known to be important, we still lack information on the existence of  consistent cognitive differences across habitat types, suggesting local adaptation in cognitive ability. In this project, we will determine whether natural variation in habitat quality acts as a potential selection pressure on cognitive variation in great tits, a model species for ecological cognition.
Work can include: fieldwork, habitat measures, behavioural measures in captivity, Foraging behaviour during winter; Starting date: any date
Supervision contact details: Kees van Oers (k.vanoers@nioo.knaw.nl); Eva Serrano-Davies (e.serrano@nioo.knaw.nl)

30. Animal Personality

Animal personality; a topic that has received much attention over the last 3 decades. Within this topic many field, lab, data or literature studies on birds are possible.  Projects could range from behavioural, ecological, fitness to genomics studies, but also studies using a large 25-year dataset on different aspects on animal personality are possible. Any length or type is possible. Study populations are either great tits or Rüppell's vultures
Starting date: Very flexible
Supervision contact details: Jorg Massen (j.j.m.massen@uu.nl) and/or Kees van Oers (k.vanoers@nioo.knaw.nl)

31. The role of birds for managing Oak Processionary Caterpillars

Oak processionary caterpillars (Thaumetopoea processionea ; OPC) have increased in abundance greatly over the last decade. They are seen as a pest, because of their venomous hairs, which can cause skin irritation in humans. Over the past years the role of songbirds, predominantly the great tit (Parus major), as a pest management tool has been widely advocated. However, strong evidence for the effectiveness of an effect of great tits on OPC densities is lacking. In this project, you will be part of a systematic study on the role for passerines in pest management. For this purpose we setup a new nest box population (100 boxes) of great tits in ‘s Gravenlande's Buitenplaatsen around the Natuurmonumenten Bezoekerscentrum “Gooi- en Vechtstreek” . With over 600.000 visitors yearly and an increasing density of OPC, this area is ideal for this study. We look for students that want to do projects on questions related to the foraging behaviour of great tits throughout the year during nestling periods (April, May, June) and/or fledging periods (June, July, August) or winter (September-March). Also possibilities on insect ecology or combinations are possible.
Work includes: Field work in ‘s Gravenland, video recordings, camera traps, insect work, behavioural observations; Starting date: Flexible
Supervision contact details: Kees van Oers (k.vanoers@nioo.knaw.nl)

Other internships

32. Primate welfare: the effect of movement on primate overweight

Overweight is a large-scale problem in captive animals. Preventing overweight is important to promote animal welfare, since overweight may lead to several health problems, such as diabetes and cardiovascular diseases. Also in group-housed macaques that live in spacious enclosures, a portion of the animals carry a few extra pounds. Preliminary data indicate that overweight animals do not have a higher food intake, but are more often inactive. We seek confirmation of this connection between behaviour and overweight. Moreover, we plan to test the effect of a change in animal management on overweight. This contributes to our understanding how management can be adjusted to improve animal welfare.
During a nine-month internship on the macaques living at the Biomedical Primate Research Centre (Rijswijk, NL) you will participate in a project that aims to enhance healthy behaviour in macaques.
Researcher: Dian Zijlmans (email: d.g.m.zijlmans@uu.nl)
Application: internships are available, preferably starting between October and January

Requirements: course in 'Socioecology'; course in statistics

ZOO welfare program

33. Monitoring behaviour and welfare of intact and castrated male Western lowlandgorillas (Gorilla gorilla gorilla) in Dutch zoos (Apenheul)

In EAZA zoos, Western lowland gorillas (Gorilla gorilla gorilla) are part of an Ex situ breeding Programme (EEP) to maintain a genetically healthy and demographically stable population. Preferably, gorillas are housed in their naturalistic social organisation of polygynous groups. However, a surplus of adult males exists for whom no place is available as harem group leaders. Finding a long-term management strategy for these animals considering their welfare is challenging. Pre-pubertal castration is one of these strategies, as this may allow these males to remain in their natal group after adulthood. However, only anecdotal information is available on the long-term effects of castration for this species. This study monitors the behaviour and welfare of intact and castrated male gorillas in Dutch zoos by observing (social) behaviour and non-invasively measuring faecal stress (-hormone) levels. You will be participating in this longitudinal study by collecting behavioural and physiological data of surplus male gorillas in seven Dutch zoos and investigating a specific research topic. Experience with behavioural observations is required for this project, as are a strong sense of responsibility, good communication skills and being able to work independently.
Internship positions available: 2
Contact person: Lisette van den Berg (Apenheul Primate Park, NL); l.vandenberg@apenheul.nl

34. Investigate the effects of restricted breeding policy on the behaviour, social dynamics and welfare of Barbary macaques (Macaca sylvanus) in three Dutch zoos (Apenheul)

Many endangered animal species in EAZA zoos are part of an EAZA Ex situ Programme (EEP); an international breeding program. Breeding policies can differ per species and range from uncontrolled breeding and restricted breeding to non-breeding (in either single sex groups or mixed-sex groups). For the Barbary macaque (Macaca sylvanus) restricted policies in mixed-sex groups currently apply: some individuals are free to reproduce, while other individuals are (temporarily) castrated or receive anti-conception to prevent reproduction. This policy offers the opportunity to breed with some of the individuals, but minimizes the amount of surplus animals in the zoo population.
As reproduction and associated behaviours (e.g. mating and rearing offspring) are an integral part of the natural behavioural repertoire of primates, they could be considered important for individual animals. However, to date, few studies have investigated the actual effects of (non-)breeding on (social) behaviour and welfare of individual animals and group dynamics in zoos. In this research, behavioural data of Barbary macaques housed at three Dutch zoos with different breeding policies is collected in this longitudinal study. This enables us to compare group dynamics and individual behaviour in groups with and without offspring. In this internship you will be responsible for the data collection and investigating the effects of (young) infants on social dynamics and individual behaviour in these groups. Experience with behavioural observations is required for this project, as are a strong sense of responsibility, good communication skills and being able to work independently.
Internship positions available: 1
Contact person: Lisette van den Berg (Apenheul Primate Park, NL); l.vandenberg@apenheul.nl

Other major/minor research topics

35. Primate welfare: overweight in semi-free ranging Japanese macaques

Overweight and obesity are a large-scale problem in captivity, with 10-15% of captive macaques developing obesity somewhere during their life (West & York, 1998). As activity is limited, food is abundant and easily accessible, living in captivity can be considered an “obesifying” lifestyle (Dittus, 2013). Although semi-free ranging macaques have more natural and spacious homes compared to captive primates, they tend to become overweight as well. We hope that comparing overweight and behaviour of macaques in different housing conditions provides more insight about which factors are related to overweight. This contributes to our understanding of what may cause overweight in group-housed macaques and hopefully result in new management strategies to improve animal welfare.
During a six- or nine-month internship, you will participate in a project that quantifies overweight and behaviour of Japanese macaques living semi-free ranging at the Affenberg in Austria (https://www.affenberg.com).
This internship requires a motivated student that is willing to spent at least five months abroad, preferably starting in February/March. The student needs to be able to work independently (as the daily supervisor will be guiding tours during the summer), but also be a team-player.
Researcher: please contact Dian Zijlmans at d.g.m.zijlmans@uu.nl
Application: flexible
Requirements: course in 'Socioecology'; course in statistics

The BPRC Primate Welfare Program

The BPRC houses primates and aims at achieving the highest standards of their welfare. The primates are  group-housed and have large enclosures with many enrichment devises. An enrichment manual is output form this research program.
Continuing research aims at further improving primate welfare, improving on each of the three R’s. Research can be conducted in three species: rhesus macaques, long-tailed macaques and common marmosets; on the following topics:
-General behaviour
-Social behaviour
-Husbandry
-Enrichment
-Positive reinforcement training
-Physiology
-Non-invasive techniques
For information contact:
Liesbeth Sterck: e.h.m.sterck@uu.nl
Annet Louwerse: Louwerse@bprc.nl
Links: BPRC

Minor research projects

Pragmatics in guereza colobus monkey (Colobus guereza) communication

For a master student EB:BE interested in gaining experience in (experimental) fieldwork, a (non-funded) minor research project position is available at the Budongo Conservation Field Station, Uganda.
Fieldwork will be conducted from November 2018 – January 2019 under supervision of Dr. A.M. Schel. She will travel to Uganda with the student and will offer training on field methods for two weeks at the start of the fieldwork period.
Scientific framework:
Although some animal calls appear to function as highly informative ‘word-like’ signals, it was recently suggested that many signals are not produced as context-specific as previously claimed, and that listeners’ adaptive responses are more fundamentally dependent on additional cues to infer the underlying cause of calling (i.e. pragmatic inference). This study will investigate which cues guereza colobus monkeys (Colobus guereza) take into account when responding adaptively to conspecifics’ vocal eagle alarms and dawn chorusing. These vocalizations are acoustically similar, but produced in different contexts, leading to highly differential responses that are needed from recipients.  A playback experiment is conducted to find out whether call-acoustics or additional cues (e.g. daytime) cause listeners to respond adaptively.
If you are interested in doing your minor research project on pragmatic inference in wild black-and-white colobus monkeys in Uganda, please contact Anne Marijke Schel A.M.Schel@uu.nl
 

Fauna conservation and certified forestry in Central Africa

Protection of wildlife in nature reserves is important. However, also protection wildlife in forests that are used for selective logging can also provide a major contribution to maintaining wildlife populations. In this research, we determine the effect of logging practices on wildlife densities in Central Africa. We also measure hunting pressure.
Minimum length of student research: 6 months (data collection, processing of data and writing of student report). Minor/major research project.
Application: Please send your application to Joeri Zwerts (j.a.zwerts@uu.nl), at least one month before the start of your research project/internship. The availability of research positions will depend on the planning of the introductions.
Requirements: Students participating in this research are required to have followed courses in ‘Socioecology’ and in statistics.

Internships at the Centre for Research and Conservation, Antwerp Zoo, Belgium

The Antwerp Zoo Centre for Research and Conservation (CRC) is the research department of the Royal Zoological Society of Antwerp (RZSA). Research activities take place mainly at ZOO Antwerpen at the ZOO Planckendael, and in associated institutions.
Students that would like to conduct a master project can contact Zjef Pereboom (Zjef.Pereboom@kmda.org) or Marjolein Osieck (Marjolein.Osieck@kmda.org). Please indicate your master program; your interests (e.g. zoo animal welfare; conservation genetics; social behaviour; cognition; et cetera); why you want to conduct research at the CRC, Antwerp Zoo, Belgium; when you would like to start; and how much time you can spend (for Major research project: 9 months). For more information about research done at the CRC visit www.zooscience.be.

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