Fear effects on population dynamics

For a great 3-minute video summary of our work, click here! We experimentally demonstrated for the first time in free-living wildlife that the fear predators inspire can itself reduce the number of offspring prey produce per year (Zanette et al. 2011, Science [PDF]), and we have now experimentally demonstrated for the first time in any free-living wild animal of any type that this can extend to fear iteself significantly reducing prey population growth rates (Allen et al. 2022, PNAS [PDF]).

Trophic cascades caused by fear of large carnivores

For a great 6-minute PBS NOVA video summary of our work, click here! We experimentally demonstrated for the first time in free-living wildlife that the fear large carnivores inspire can itself cause cascading effects down food webs critical for conserving ecosystem function. Our results reinforce the need to conserve large carnivores given the significant ‘‘ecosystem service’’ the fear of them provides (e.g. Suraci et al. 2016, Nature Communications [PDF]).

Fear of the human "super-predator"

Much of the world now consists of human-dominated landscapes, yet there has been little research regarding how humans affect trophic networks through behavioural responses. We have shown that humans can be far more frightening than any other predator and alter the ecological role of carnivores. Human disturbance may have widespread ecological effects on many species by altering feeding behaviour and resulting in human-induced trophic cascades (e.g. Suraci et al. 2019, Ecology Letters [PDF]).

Fear effects in the brain

Current models of fear are based on post-traumatic stress disorder (PTSD) in humans. We are extending these models to understand neurobiological effects of predator fear on wild animals with experiments simulating acute and chronic predation risk and quantifying the effects in brain regions implicated in mammalian and avian fear networks. We are incorporating this new information into the biomedical model of fear and the field of predator-prey ecology (e.g. Zanette et al. 2019, Scientific Reports [PDF]).

Summary of Ecology of Fear

Zanette et al. 2011. Perceived predation risk reduces the number of offspring songbirds produce per year. Science. [PDF]

Our Work Featured on PBS NOVA's Animal Espionage!

Facilities Available to Lab Members


We conduct field experiments on birds and mammals throughout the world, typically in collaboration with other leading researchers. Please see the Collaborations and ABR System pages for examples and details.

Liana with Professor Craig Packer in South Africa

Advanced Facility for Avian Research

AFAR is home to the world’s first hypobaric climatic wind tunnel for bird flight - allowing research into the physiology and fluid dynamics of bird flight in high altitude conditions.  In combination with specialized indoor and outdoor holding rooms and cutting edge experimental and analytical facilities, AFAR is a leading centre for the study of avian neurobiology, physiology and behaviour.

Hypobaric Avian Wind Tunnel

Behavioural Observation Rooms

On-Site Laboratories

Environmental Sciences Western Field Station & Elginfield Observatory Forest

Environmental Sciences Western is a Faculty of Science field station located approximately 14 km north of the main Western campus.  It is used for inter and multidisciplinary research by faculty in the Departments of Biology, Physics and Astronomy and Geology, along with researchers from the Faculty of Engineering and Agriculture and Agri-Food Canada.


Highlighted News

New PNAS paper [PDF]
Fear of predators in free-living wildlife reduces population growth over generations

Fear itself can halve wildlife populations in 5 years or less!

We report experimentally demonstrating for the first time in any free-living wild animal that the fear predators inspire can itself reduce prey population growth rates. Fear itself caused cumulative, compounding adverse effects on fecundity and every component of offspring survival, reducing the number of young reaching adulthood by 53%. Moreover, these adverse effects extended to those reaching adulthood showing evidence of impaired brain development likely to shorten their survival during adulthood – representing a transgenerational impact reducing population growth over generations.