Human super-predators not always ‘super-scary’ to wildlife, finds study

Humans have climbed to the top of the food chain by skillfully hunting, trapping, and fishing for other animals at scales that far exceed other predators, altering how the animals behave and earning the tag of a “super-predator”. But a new study led by the Centre for Ecological Sciences, Indian Institute of Science (IISc), suggests that there is a bit more nuance to this idea.

While animals clearly respond with fear to humans who hunt or kill, they are far less consistent in how they react to non-lethal human presence.

A comprehensive meta-analysis, published in Ecology Letters, analyses three decades of research on how wild animals change their behaviour in response to different types of human interactions. The study examined behavioural shifts in foraging, vigilance, and movement across species and ecosystems to look into whether humans are always super-scary.

“The short answer is: no, not always,” says Shawn D’Souza, PhD student at CES and the study’s lead author. “We found strong evidence that lethal humans such as hunters and fishers are indeed perceived as threatening. Animals in areas exposed to lethal humans tend to be more vigilant and spend less time foraging. In contrast, responses to non-lethal humans, such as tourists or researchers are weaker and more variable.”

An IISc release said passive human structures like roads and settlements sometimes reduced animal vigilance. “In certain cases, these areas can function as perceived refuges,” D’Souza explained. “Predators often avoid humans, which can make areas near people feel safer for some prey species.”

Another reason is that areas adjacent to roads are often cleared of thick vegetation, making them attractive grazing sites for smaller animals, said co-author Maria Thaker, Professor at CES. But these sites still pose the risk of vehicular collisions.

The researchers chose foraging, vigilance, and movement as the behavioural parameters because these help capture trade-offs that animals face when managing risk. “Time spent being vigilant is time not spent feeding. Changes in animal movement affect energy expenditure and access to resources. Because these behaviours directly affect survival and reproduction, they offer a clear window into how fear of humans can shape wildlife populations over time,” said the release, adding that the study’s findings broadly support the “risk allocation hypothesis,” which suggests that animals adjust their behaviour based on how intense and predictable a threat is. When danger is high and consistent, animals stay cautious, says D’Souza. When risk is low or predictable, they can afford to relax.

Beyond individual behaviour, the researchers point to a bigger picture. Changes in fear and behaviour can cascade through ecosystems, altering grazing, predation, and ecological balance. According to co-author Kartik Shanker, Professor at CES, the effect of lethal impacts on behaviour can actually help manage conflict. A small amount of culling may greatly reduce the ingress of wild animals in human-dominated areas compared to a range of other approaches currently in use, he said.

“We need more predictive frameworks that link behavioural responses to ecological and evolutionary context. That includes incorporating species traits, past exposure to humans, predator communities, and landscape structure,” said Mr. D’Souza, adding that long-term and experimental studies will be key to understanding whether animals are simply getting used to humans or undergoing deeper evolutionary changes.