The impact of tourist visits on mountain gorilla behavior in Uganda

Close encounters with mountain gorillas: Tourists gone bananas!

Are gorillas at risk? We analyse the behaviours of tourist adhering to rules and the stress levels of gorillas to promote healthy gorilla tourism.


Mountain gorillas are a species in danger of extinction. The current population of mountain gorillas consists of only 1,000 individuals, dispersed across two subpopulations in Uganda, Rwanda, and the Democratic Republic of the Congo. Despite being widely recognised and cherished by the public, protecting mountain gorillas is complex and challenging.

Video Summary of article

Unlike other endangered species like Oryx, California Condors, or Golden Lion Tamarins, mountain gorillas cannot be effectively preserved through captive breeding programs. In fact, mountain gorillas do not survive well in captivity and cannot thrive for more than a few days or months. This makes breeding and sustaining their population a significant challenge. Moreover, their natural habitat is threatened by mining and logging companies, poachers and civil war.

In such challenging environments, it is still possible for different stakeholders to come together and find solutions that benefit both human and non-human animals’ problems. This includes addressing the needs of gorillas, who require suitable habitats and resources for survival, as well as meeting the requirements of humans, who also seek suitable homes and resources for their well-being.

Journey of habituation: Bridging the gap with wild gorillas

During the 1960s, scientists formulated a comprehensive plan to preserve the habitat of gorillas and ensure the well-being of local populations by offering them alternative livelihoods, thus mitigating the necessity to exploit or harm the forest. This plan hinged upon establishing a carefully regulated and specialised form of gorilla tourism, enabling visitors to observe the magnificent creatures while contributing through a fee-based system. The revenue generated from these fees would then be shared with the local communities through the direct distribution of funds on top of creating jobs related to the tourism sector.

Of course, the real stars were the gorillas and therefore, strict safety regulations were put in place to avoid disease transmission between animals and humans (and vice-versa) and to avoid stressing the animals. Currently, such rules include excluding sick people from visiting the gorillas, a maximum of 8 people per group, one group per day for a maximum of 1 hour of contact with the gorillas, and a safety distance of a minimum 7-meter to the animals. But despite these efforts, diseases – often fatal – have spread from humans to gorillas. Respiratory outbreaks afflict mountain gorillas annually, and the occurrence of measles outbreaks has necessitated the vaccination of wild mountain gorillas. In contrast, their closely related species, the western lowland gorillas, have experienced a 95% mortality rate due to Ebola, with susceptibility to COVID-19 infection presenting an additional risk.

Balancing Act - Gorilla Tourism: Navigating Environmental Threats, Conservation, Economic Benefits, and Emerging Challenges.
Figure 1. Balancing act – Gorilla tourism: Navigating environmental threats, conservation, economic benefits, and emerging challenges.
Credit. Author

Uncovering gorilla reactions and exploring stress levels in the presence of tourists

Based on preliminary data, our study aimed to investigate the compliance rates of tourists with the 7-meter rule in gorilla tourism activities. We were particularly interested in examining how tourists’ adherence or non-compliance with this rule would affect the behaviour of the gorillas. We targeted behavioural stress signs and the social behaviours of gorillas, looking for potential coping strategies (e.g., social buffering). We travelled to Bwindi Impenetrable National Park in Uganda and met with one of the oldest gorilla families habituated to tourists. It is noteworthy that the majority of its members were born after the commencement of the habituation process. We followed Rushegura throughout one year and collected 577 hours of gorilla behaviour.

Initially, we anticipated daily climbing and inclement weather would pose our primary challenges. However, to our surprise, the main obstacle we encountered while testing the 7-meter rule was the unfortunate reality that tourists seldom adhere to this regulation, spending less than 15% of their viewing time at a distance of 7-meter or more from the gorillas. Consequently, we lacked sufficient data beyond the 7-meter threshold to conduct comparative analyses of gorilla behaviour. Whether associated with the recent selfie-hunting trend or not, we found that tourists spend most of their time (60%) within 3-meter of the gorillas. So, we switched our aim to two more realistic ones: 1) to compare the gorillas’ behaviour before, during and after the tourist visit and 2) to compare the gorillas’ behaviour within 3-meter of the tourists and above 3-meter of the tourists.

Upon analysing specific behaviours (scratching, social behaviour, feeding and interactions with tourists), our models exhibit heightened stress indicators during tourist visits, particularly males displaying acute stress when tourists are within a 3-meter proximity. Furthermore, our findings indicated that gorillas tend to respond by either attacking or avoiding tourists when they come too close. In other words, we found the imminent risk for the pathogenic spill (via close and physical contact), exuberated by the fact that animals under stress may have compromised immunity.

Gorillas are also more likely to decrease feeding time and engage in social behaviour when tourists are present and within 3-meter, which is probably a mechanism to reduce stress through social buffering. Similar effects were found in different species also facing strong tourism pressure (e.g. Barbary macaques and longtailed macaques). The difference between gorillas and these species is that gorillas weigh around 150 kilograms (and could potentially cause severe injury to a distracted tourist). During our interactions with gorillas, we consistently noted their lack of hostility towards humans as long as we maintained a minimum distance of 7-meter. It was interesting to observe that this distance coincided with a decrease in stress levels exhibited by the gorillas.

Figure 2. The ripple effect – Exploring negative impacts and the potential for pathogenic spillover in gorilla tourism.
Credit. Author

Encouraging responsible encounters and inspiring respectful distancing with gorillas

All of this was achieved before the pandemic. Throughout the pandemic, the national park remained closed, and upon reopening, the authorities implemented mandatory mask-wearing and hand disinfection measures. However, we lack specific data regarding compliance with recommended distances at present. Nevertheless, several testimonials recount emotionally captivated tourists approaching gorillas in uncomfortable proximity.

Recent studies show strong and assertive messages can deter tourists from disrespecting the rules. Still, the education of potential tourists needs to begin in their home countries (e.g., through social media campaigns for more ethical tourism and selfie codes). Enhanced training (and advantages) for park personnel responsible for enforcing regulations, along with the requirement of vaccination proof before visiting, can be implemented to safeguard the well-being and health of gorillas.

Preserving nature’s treasures and empowering communities

Gorilla tourism has played a significant role in the remarkable increase in the mountain gorilla population over the past decade. This has led to their reclassification from critically endangered to endangered species. The income generated from the parks visited by gorilla tourists is also allocated to support parks that remain inaccessible to tourists, thereby benefiting both the wildlife and local communities within the immediate vicinity of the gorillas’ habitat as well as beyond its boundaries. Importantly, it helps to deter oil and mineral companies from encroaching on these forests and promotes international cooperation among the countries home to gorillas. 

Figure 3. Innocence amidst the wild – An infant mountain gorilla in the Rushegura Group, Bwindi Impenetrable National Park, Uganda (Jully, 2018).
Credit. Author

The collective and enduring commitment to sustainable Gorilla tourism, prioritising gorillas’ health and welfare, is key to safeguarding gorillas, natural resources and local communities’ livelihoods for generations to come.

This study was supported by the Leading Graduate Program in Primatology and Wildlife Science, Kyoto University, JSPS fellowship #22F22011 to Raquel Costa, Grants-in-Aid for Scientific Research from JSPS/MEXT KAKENHI #16H06283 to Tetsuro Matsuzawa, #15H05709 to Masaki Tomonaga, JP17H06381 in #4903 to Yasuo Ihara, and JSPS Core-to-Core A. Advanced Research Networks CCSN to Tetsuro Matsuzawa.


Journal reference

Costa, R., Takeshita, R. S., Tomonaga, M., Huffman, M. A., Kalema-Zikusoka, G., Bercovitch, F., & Hayashi, M. (2023). The impact of tourist visits on mountain gorilla behavior in Uganda. Journal of Ecotourism, 1-19.

Raquel's research focuses on the welfare and behavioural adaptability of animals in their interactions with humans. She obtained her doctoral degree from Kyoto University, studying mountain gorillas in Uganda's Bwindi Impenetrable Forest. In the past, she also studied the welfare of captive chimpanzees, monkeys, macaques, and lemurs in Portugal, Spain, and Japan. Currently, Raquel is a postdoctoral fellow at the Japan Monkey Centre and is affiliated with the Primate Cognition Research Group in Portugal. Her ongoing work involves investigating the interactions between gorillas and humans while exploring the underlying reasons behind people's strong attraction to animals.