Top predators’ fear of human ‘super predator’ can impact entire ecosystems
Cougars and other large carnivores are frightening beasts but, according to a new study, the fear these top predators inspire may be matched by their own fear of the human ‘super predator’, causing cascading effects down the food chain.
Globally, humans now kill large carnivores at over nine times the rate they are killed naturally, and new research by a team from Western University and the University of California Santa Cruz (UCSC) demonstrates that top predators, like cougars, have learned to fear the human 'super predator', altering the role of large carnivores in the ecosystem.
These findings by Liana Zanette from Western's Faculty of Science, in collaboration with
Zanette, a professor in Western's Department of Biology, and her colleagues experimentally demonstrated that cougars perceive humans as predators, fleeing at simply hearing humans speaking and consequently feeding less when they think humans are nearby, necessitating their killing more prey to compensate.
"Our previous research has shown that fear itself can shape ecosystems, and the fear large carnivores inspire in their prey helps maintain ecosystem health. These new results indicate that, by frightening top predators, the fear of humans has been superimposed on the natural 'landscape of fear', meaning humans may be distorting ecosystem processes even more than previously imagined," explains Zanette, a renowned wildlife ecologist. "These results thus have critical implications for conservation, wildlife
The team conducted the study on cougars living in rural and suburban areas near Santa Cruz, California. To experimentally test their fearfulness of humans, the team played
Large carnivore numbers have declined worldwide as a result of hunting and persecution by humans, and habitat loss.
Legal protections and conservation initiatives have reversed these declines in many parts of North America and Europe and large carnivores increasingly inhabit human-dominated landscapes, evidently living in fear, surrounded by the human 'super predator'.
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