Fear of Humans

Posted on the 28 August 2025 by Bradshaw @conservbytes

Many animals avoid contact with people. In protected areas of the African savanna, mammals flee more intensely upon hearing human conversations than when they hear lions or sounds associated with hunting. This fear of humans affects how species use and move in their habitat.

Throughout our lives, we interact with hundreds of wildlife species without stopping to think about it. These interactions can be direct, such as encountering wild animals while hiking in the mountains or driving through rural areas — or more deliberate, as when we engage with wildlife for food, sport, or trade. As hunters, fishers, and collectors, we kill more than 15,000 species of vertebrates — one-third of known diversity — a range of prey 300 times greater than that of any other predator our size (1).

Now, let’s look at it from the other side. Anyone who has survived an attack or a fatal accident, they understand that the experience is remembered for a lifetime. Likewise, animals store information about threatening or harmful encounters with humans (2). For them, adjusting their behavior in response to human presence has implications for their survival and reproduction (3, 4), which are passed down from generation to generation (5). This ability to adapt, for example, determines which individuals, populations and species coexist with us in urbanised environments (6).

Response to dangerous sounds

Liana Zanette and her team measured the flight responses of wild mammals in the Greater Kruger National Park (South Africa) when exposed to sounds that signal danger (7) [video-summary]. To do this, Zanette recorded videos of more than 4,000 visits to 21 waterholes by 18 mammal species. During each visit, a speaker attached to a tree randomly played one of five playback sounds: hunting dogs barking, gunshots, lion growls, human conversations in a calm tone and, as a control, the songs of harmless birds.

Large mammals at waterholes in the Greater Kruger National Park (GPNK, South Africa) (7). GPNK covers an area of 1,800 km² to the east of Kruger National Park (19,500 km²). While Kruger is state-owned, GPNK is managed by private and community landowners. It has no fences, allowing free movement of animals between the two parks. The top three photos show: two lions (Panthera leo), a herd of African elephants (Loxodonta africana), and groups of common hippos (Hippopotamus amphibius) and African buffalo (Syncerus caffer). To study the flight response of Kruger’s mammals to threatening sounds (7), the bottom two photos illustrate the distance from the water to the speaker-video [ABR] device, which was secured to a tree inside a steel bite- and impact-proof case, and a leopard (Panthera pardus) fleeing after hearing a recorded human conversation, leaving behind an impala (Aepyceros melampus) it had just captured at a waterhole. The playback dialogues used in the experiment were in local languages: Afrikaans, English, Northern Sotho, and Tsonga. See documentaries on Kruger: (i) Aerial Africa: Kruger National Park, (ii) A guide to Kruger Park 2023 Wildlife and (iii) Exploring Klaserie: untamed & wild in the Greater Kruger. Overall, waterholes (see Kruger video-examples here, here and here), both natural and artificial, play a crucial role in shaping the ecology of African savannahs by influencing wildlife distribution, vegetation dynamics and overall ecosystem health. Photo credits: Naas Rautenbach (lions) and Liana Zanette.

Overall, animals fled in one out of every three recorded scenes. The four dangerous sounds caused them to flee before and more frequently than the bird songs. Notably, animals fled twice as often and 40% earlier upon hearing human voices compared to lion growls. The average time to abandon a waterhole varied by sound: 14 seconds (humans), 23 seconds (dogs, gunshots, lions), and 32 (birds) seconds. Response times (medians) also varied by species: from 2 seconds (African wild dog Lycaon pictus) to 100 seconds (African elephant Loxodonta africana).

Weighing up to 200 kg, the lion (Panthera leo) is Africa’s largest feline and the continent’s apex predator, capable of hunting virtually any animal, including young elephants (8) — see lion facts and documentary list on this big cat. Since the Pleistocene, lions and humans have shared territories, both employing highly effective group-hunting strategies (9).

Flight behavior in 18 mammal species of Greater Kruger National Park (South Africa) in response to sounds played at 21 waterholes (7). See research video-summary. Using an ABR [Automated Behavioural Response] electronic device, sounds were played at 60 decibels (audible volume at 10 m) following this sequence: a video sensor detected an animal at 15 m, the camera began recording for 3 seconds, the speaker emitted a playback sound randomly for 10 seconds, and the camera continued recording for another 17 seconds (total scene duration = 30 seconds). A total of 4,239 videos were recorded in response to 14 variations of five playback types: hunting-dog barks, gunshots, lion (Panthera leo) snarls and growls [listen], human conversations and bird songs. The sample included over 800 scenes per sound, varying according to the natural abundance of each species: from 27 recordings of leopards (Panthera pardus) to 991 of the many impalas (Aepyceros melampus). Results showed that animals fled 8 times more often when hearing human voices than when hearing bird songs (yellow bars), and the time taken to leave the waterholes was 40% shorter with human dialog than with bird songs (blue bars). The flight responses were milder for the other sounds. For the 9 most flight-prone (herbivore / carnivore) species, the two lower graphs show that hearing human voices triggered a higher percentage of flight responses and shorter times to leave the waterholes compared to hearing lions (with time measured on a logarithmic scale: 1 (= 10 s) to 2 (= 100 s). Only the African elephant (Loxodonta africana) fled more often when hearing lions, but they left the waterholes sooner when hearing human voices. The opposite pattern was observed in leopards.

However, only our species can be considered an ‘unsustainable superpredator’ (10). Unlike other carnivores, (i) humans are overpopulating the Earth, and (ii) our ability to kill has no natural limits: it is not solely dependent on physical skill, but also on advanced technologies that are regulated to some extent by cultural factors such as resource-exploitation laws.

Research like Zanette’s (7) suggests that wildlife has learned to fear us: they definitely know how we roll. Importantly, if animals avoid humans in protected areas where activities are regulated to varying degrees, this avoidance, and its impact on species’ life histories, is likely to be even more pronounced outside these zones, depending on the type and intensity of human activities.

Fear as part of the landscape

The concept of the “landscape of fear” refers to how animals perceive the risk of being attacked depending on where they are within their habitat (11) — related to the concepts of ecology of fear (12) and nonconsumptive effects (13). A lower presence of wildlife in an area frequented by a predator, whether human or animal, does not necessarily mean the predator has wiped them out; rather, their prey might have simply moved elsewhere (14).

Thus, in the African savannah, large herbivores tend to avoid waterholes that lions frequent, especially at night when the king of the jungle is out hunting (15). The landscape of fear intensifies with the mere presence of humans, and its effects ripple through the food web. A clear example is the mountain lion (Puma concolor) in North America. These carnivores avoid urbanised areas or take longer to return to them after encountering people (16). As a result, deer populations increase in these areas, leading to more intense browsing of vegetation and a shift toward shrub-dominated landscapes (17).

Human presence shapes the behavior and movement of wild animals, even if they remain unseen and even in protected areas. This cause-and-effect relationship is difficult to measure and has been studied more in conspicuous bird species (18). Zanette argues that many species react negatively to human voices in a systematic way (7). Guided by fear, they flee without pausing to assess whether a person is harmless (e.g., walking or taking photographs) or dangerous (e.g., armed with rifles). This justifies setting visitor quotas for parks and reserves, a practice already in place in Western countries.

Nevertheless, in Africa many protected areas rely on tourism for funding, making it inadequate to restrict visitor numbers (19). Alternative strategies might be needed to help animals become accustomed to human presence, as has been done with gorilla and great ape tourism (20) — see TED talk and expert discussion.

However, these measures are controversial (21). Familiarisation with humans could lead to behaviours resembling domestication, potentially making prey more vulnerable to their natural predators (22). Ultimately, understanding and mitigating the pervasive “landscape of fear” caused by human presence is crucial, not only for conserving wildlife populations, but also for preserving the delicate balance of ecosystems on which our own survival depends.

Salvador Herrando-Pérez

References

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