Ape behavioural flexibility is the ability to change daily routines when conditions change. A large 2025 review shows how far great apes now do this wherever people reshape their forests. For Paper I it is a compact, current example of primate adaptation that also touches conservation.
Source: Gilbert and Kalan, Primates 66(2), 2025, a systematic review of great-ape responses to human disturbance.
What the review examined
The authors screened close to 2,500 studies and kept 96 of high quality. Together they cover all seven living great apes: chimpanzees, bonobos, eastern and western gorillas, and the Bornean, Sumatran and Tapanuli orangutans. That makes it one of the broadest assessments of how apes respond to people. Even so, a review can only be as even as the studies it pools.
How disturbance reaches the forest
The most frequent pressure was land-use change: forest converted to cropland, logged for timber, or cut up by roads and settlements. As a result, traditional ranging patterns break down, and apes have to adjust where they feed, travel and sleep.
What apes did in response
Across regions the apes changed their behaviour in several ways. Some took up crop foraging on human-grown food. Others shifted nesting to new sites or changed how often they reused nests. Others used human roads to travel more easily. In short, these are flexible responses, learned or adjusted within a lifetime, rather than fixed instinct.
Flexibility Is Not Always Protection
Safer adaptations
- Changes in nesting helped apes avoid direct human contact and carried no negative outcome.
Riskier adaptations
- Crop foraging and road use were linked to stress, injury, mortality and human–ape conflict.
Species and context differ; behavioural flexibility does not always reduce risk.
Safe adaptations versus risky ones
The review separates low-risk from high-risk responses. Changes in nesting often helped apes avoid direct contact with people and were not linked to negative outcomes. Crop foraging and road use, by contrast, were linked to stress, injury, mortality and human-ape conflict, because they expose animals to retaliation, vehicles and disease. Flexibility does not guarantee survival. It can even pull an animal into a trap.
Species and context matter
Responses differed by place and species. Some gorilla populations avoided logged forest entirely, while others entered it to use new foods. Local ecology, species traits and the intensity of disturbance all shape what an ape does. So avoid writing as if there were a single "ape response".
What this means for anthropology
For anthropology the review does three things. It documents behavioural plasticity in non-human primates. It shows that adaptability is a trait we share with other apes, which is a useful comparative point. And it feeds conservation anthropology, because policy has to recognise that some adaptations raise conflict instead of reducing it. Remember that behavioural flexibility within a lifetime is not the same as evolutionary change, although over many generations it can shape the pressures selection acts on.
Using it in UPSC Mains
It sits under Paper I, Section 1.5, where the syllabus lists primate behaviour. Use it as a modern illustration of flexibility in questions on primate behaviour and adaptation, and as an ecology-plus-conservation example. Next, say what the review found. Then add the limit: results vary across species and sites, and a review shows association, not a controlled experiment.
The closest exam question is Jane Goodall and Primate Behaviour (2020); this evidence is a contemporary addition to that kind of answer. More questions are in the Human Evolution and Primatology PYQs. For related reading, see Orangutans and Metabolic Flexibility and Jane Goodall and the study of chimpanzee behaviour. The Anthropology Optional complete guide shows where this topic sits in the full syllabus.
Sources
Gilbert, M. A. and Kalan, A. K. (2025), systematic review of great-ape behavioural responses to anthropogenic disturbance, Primates 66(2).