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Monkeying around: Can Caregivers be an effective source of social enrichment for lab-housed monkeys?

Updated: Jun 2, 2022

This blog post was written by Rachel van Vliet and Simran Prasad.

This summer, we are happy to announce that CowLife McGill has expanded its research base to include Monkey Life for the first time! As part of their Master’s degrees, Rachel van Vliet and Simran Prasad (see Image 1) have been conducting this new project to look at the use of human caregivers as a form of social enrichment for monkeys used in laboratory research. Providing appropriate enrichment to captive primates is essential to their well-being. It not only occupies their time to alleviate boredom, but can act to stimulate species-appropriate behaviours and, ideally, help reduce abnormal behaviours, which are indicative of stress. Enrichment can come in many forms, from providing toys, food puzzles, altering diets, to adding a social companion. It can often be difficult to provide adequate enrichment in laboratory environments due to the availability of materials, time, and restrictions from project protocols. The aim of this project is therefore to see if caregivers can be used as an additional source of social enrichment, as they are already present in the daily lives of the monkeys and have the opportunity to form long-term relationships with them.

Image 1. From right to left, Rachel and Simran in full personal protective equipment at the lab.

In order to evaluate the use of caregivers as social companions to the monkeys, the monkeys will be split into two groups and receive one of two treatments: human behaviour or monkey-like behaviour. During regular afternoon feeding times, the caregivers will spend an additional 4 minutes per day interacting with the monkeys. Monkeys receiving human behaviour will have the caregivers speaking to them the way humans would engage with each other: saying hello, talking to them quietly, openly narrating what they are doing, and so on. The monkeys receiving monkey-like behaviour will have caregivers avoid making eye contact or speaking and imitate monkey behaviours to the best of their abilities, such as lipsmacking while offering food or grooming. In order to facilitate grooming in a safe way, caregivers will be wearing wristbands made of fake fur (see Image 2). The goal is to see if there is a benefit to both the extra time spent interacting and/or to the different types of interactions being provided (human or monkey-like).

Image 2. Fake-fur wristbands worn by caregivers on top of regular personal protective equipment.

Over the course of the project, we will be measuring the short, mid, and long-term effects of the interactions on the monkeys. In the short-term, we will take live observations during treatment to see how the monkeys react to the caregivers over the course of the experiment. For mid-term effects, we will be taking weekly videos of the monkeys when no humans are present to see how their weekly activity budgets change over the course of the experiment, focusing on any change in species-appropriate behaviours and abnormal behaviours. Finally, for long-term measures, we will be conducting two types of welfare tests: Novel Object tests and Novel Human tests. Both consist of exposing an individual to novel stimuli and noting their reaction. For our novel object, we will be using a small traffic cone (see Image 3), which would look unlike anything the monkeys typically see in their daily lives. For the novel person, we will use an individual who does not work with the primates and will never be seen by them prior to the test. The theory behind both tests is that better-adjusted individuals with a higher degree of welfare will react better to novel stimuli. While there is always an effect of individual personalities affecting a monkey’s response to the stimuli, the monkeys’ reactions will be compared only to themselves to see if there is a change from the beginning to the end of the trial. Ideally, if the treatments have a positive effect on the overall welfare of the individuals, we will find that the monkeys respond more positively to the novel object and person at the end of the trial.

Image 3. Novel object (left picture) and Simran (right picture) with the mechanism that will drop the novel object.

We hope that our project will lead to an increased understanding of social enrichment provided by humans as an effective way of managing boredom in captive monkeys and promoting species wellbeing. In doing so, we hope to contribute to the enhancement of animal care by establishing evidence-based guidelines for the proper care of non-human primates in research. Our results could further serve to inform future training of caregivers and the design of husbandry protocols in captive settings. We are very excited to be starting this project and look forward to updating you along the way!



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