New Delhi: Scientists at the Centre for Ecological Sciences (CES), Indian Institute of Science (IISc), have found that wild animals respond strongly to lethal human activities such as hunting and fishing but show weaker and inconsistent reactions to non-lethal human presence.
The researchers published their findings in the journal Ecology Letters after conducting a comprehensive meta-analysis of nearly three decades of global research. The team analysed how wild animals changed their behaviour in response to different types of human interactions across ecosystems and species.
The study examined key behavioural patterns such as foraging, vigilance, and movement, the IISc said in a press release. The researchers found strong evidence that animals exposed to hunters and fishers increased vigilance and reduced the time spent feeding. In contrast, animals showed more variable and often weaker responses to non-lethal human activities such as tourism and research.
Lead author Shawn D’Souza, a PhD scholar at CES, reported that lethal human presence consistently triggered fear responses in wildlife. He explained that animals adjusted their behaviour when they faced direct threats, but reacted less predictably when human presence did not involve harm.
The study also found that passive human infrastructure, such as roads and settlements, sometimes reduced vigilance in certain species. The researchers observed that some prey animals used areas near humans as perceived refuges because large predators often avoided human activity.
Co-author Maria Thaker, Professor at CES, noted that roadsides frequently have cleared vegetation, which attracts grazing animals. However, these areas still expose wildlife to risks such as vehicle collisions.
The researchers selected foraging, vigilance, and movement as indicators because these behaviours reflect how animals balance survival trade-offs. Time spent staying alert reduces feeding opportunities, while changes in movement affect energy use and access to resources. These behavioural adjustments directly influence survival and reproduction.
The findings support the “risk allocation hypothesis,” which states that animals adjust their behaviour based on the intensity and predictability of threats. The researchers found that animals remained cautious when danger remained frequent and severe, but relaxed when threats appeared predictable or minimal.
Co-author Kartik Shanker, Professor at CES, said that lethal management measures can influence animal behaviour in ways that may help reduce human-wildlife conflict. He stated that limited culling could reduce the movement of wild animals into human-dominated landscapes more effectively than some existing approaches.
The researchers emphasised the need for stronger predictive frameworks that link behavioural responses to ecological and evolutionary contexts. They called for long-term and experimental studies to determine whether animals are merely adapting to human presence or undergoing bigger evolutionary changes.
The study highlights how different types of human activity shape wildlife behaviour and influence broader ecological balance.
