by Captive chimpanzees are one of the most popular species kept in zoos due to their charismatic appeal and human likeness. They are the closest living relatives to humans due to shared genes and behavioral and psychological similarities.
Zoos have an ethical obligation to care for the animals they house. Many provide environments that take care of animal welfare needs. However, the influence of the zoo environment on animal behaviour, psychology and welfare is sometimes overlooked or poorly understood.
Historically, zoos have been criticized and labeled as “animal prisons”. But based on my experience and research, it is clear that modern zoos play an important multifaceted role as centers of education, recreation, conservation and research.
Chimpanzees have been the focus of much zoo-based research, including research on their welfare. Most people – researchers, zookeepers and the public alike – assume that larger and more “natural” living spaces improve animal welfare and existing evidence suggests that this is generally the case. .
Few studies have focused on the long-term effects of these enclosures, however.
A paper I wrote in collaboration with colleagues fills this gap. We observed a stable group of eight chimpanzees at the Johannesburg Zoo in South Africa five years after their outdoor housing was renovated to a more natural design. The chimpanzees took advantage of the new enclosure. But they seemed to use the space in an unusual way.
We discovered that the chimpanzees preferred to spend time in the space that was their original enclosure and that they formed groups with extremely tight spacing between them.
We suggest that the chimpanzees’ perception of space was altered by their previous experience of the smaller, uncleaned housing and that this restricted their use of space in the naturalistic enclosure through a self-imposed “invisible cage” of apparently.
It is not clear what role the “invisible cage” might play in other settings. However, we believe our findings have implications for animal welfare, farming and the wider conservation of endangered species.
Our paper shows that zoo-based research can teach us about the needs of the animals in our care, and how their environment and experiences shape their biology and behaviour. It can even give us a glimpse into their minds and perceptions.
Enclosures
Johannesburg Zoo turns 120 years old in 2024. Located in Saxonwold in Johannesburg, the zoo covers an area of 55 hectares and is the second largest zoo in South Africa. It hosts 320 species of animals and is a member of the World Association of Zoos and Aquariums.
In 2004, Johannesburg Zoo’s outdoor chimpanzee enclosure, built in the 1970s, underwent a major upgrade. The chimpanzee space was expanded from a pair of concrete and wooden enclosures, each 10 meters by 10 metres, to a large natural enclosure comprising approximately 2,500 square meters of grass, bushes, trees, rocks and streams, occupying the same site as the site. previous housing. Most of the chimpanzees were all living in the old enclosures and two had only lived there for a few years.
Upgrading to naturalistic designs has become the standard for zoos. They are often followed by evaluations to determine how the new space affects animal welfare. Typically, such evaluations find that natural enclosures improve welfare. This was also true at the Johannesburg Zoo. The chimpanzees showed persistent beneficial changes in behavior, such as reduced abnormal or repetitive behavior, suggesting an improved benefit in their natural enclosure.
Our study began in 2009, five years after the enclosure was renovated. In this study, the chimpanzees appeared to use the entire enclosure to some extent but showed a preference for the area where the enclosure had previously been.
Curiously, the chimpanzees appeared to have a strong tendency to form tightly spaced groups that corresponded to the exact dimensions of the former housing. These groups came together regardless of when or where the chimpanzees were in the enclosure, the environmental conditions at the time or the individual chimpanzees involved.
This unusual pattern had not been reported before and seemed contrary to what would be expected for a group of animals that had lived in a space for as long as five years. This space-use behavior appeared to reflect a perceived, self-imposed, intangible barrier to the chimpanzees’ spacing, as if the groups were surrounded by an invisible cage.
Animal welfare and use of space
Space use is difficult to interpret in terms of animal welfare as it is often context dependent and therefore often overlooked in evaluations following enclosure restoration. When an animal chooses to use a small amount of space it may be because the space is attractive and meets its welfare needs. However, an animal may choose to stay in a small area because the larger space is perceived as unpleasant or even dangerous.
For the chimpanzees, there was no indication that the spacing pattern indicated distress or compromised welfare. Other aspects of chimpanzee behavior suggested an enhanced interest in naturalistic enclosure. Instead, the invisible cage seemed to represent a persistent psychological barrier, learned in previous housing and implemented in naturalistic enclosure years later.
These findings are indicative of a psychological effect known as “learned helplessness” seen in many species, including humans. In situations where people are helpless or lack control, they find that their actions cannot affect the outcome. This attitude is brought into later situations where they can influence the outcome, while still being helpless.
Further research is needed to understand the welfare implications and wider application of these findings. However, they highlight some important issues regarding the role of zoos and the impact of zoos on species conservation.
The importance of zoos
Zoos help raise awareness of conservation issues. They also provide refuge for threatened species. Many facilities breed and reintroduce these species into the wild. Johannesburg Zoo in particular has many conservation programmes, including a breeding program for the endangered Pickersgill reed frog.
As sanctuaries that support threatened populations, zoos actively conserve biodiversity in many ways (creating gene banks, breeding animals and preserving biological and behavioral diversity) while also providing critical access to rare species for observation and research.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. Written by: Luke Mangaliso Duncan, University of Warwick
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Luke Mangaliso Duncan received funding from the Jane Goodall Institute and the National Research Foundation (NRF) of South Africa.
