Global Collaborations

We collaborate with leading researchers from around the world conducting field experiments exploring the ecology of fear in diverse different free-living wild birds and mammals. To manipulate fear we generally use playbacks of predator vocalizations though we are open to anything that works and have also used habitat modification and ‘added’ predation (prey removal) to test the effects of fear. Our goal is always to conduct fundamental research with relevance to wildlife conservation. Here we highlight the researchers we have been fortunate to collaborate with and the experiments we have accomplished with them. Many of our recent collaborations have involved the use of Automated Behavioural Response (ABR) systems we developed, which are described in more detail on the ABR System webpage.  We have 100 of these systems available for use on anything anywhere.  We are always interested in collaborations, so if you would like to collaborate with us, using ABRs or other means to experimentally test the effects of fear, please send us an email!

British Columbia (Canada)

Highlighted Collaborator: Dr. Lawrence M. Dill from Simon Fraser University

Fear of large carnivores causes trophic cascade. [PDF]

We directly experimentally demonstrated for the first time that the fear large carnivores inspire can itself cause a trophic cascade. Fear of large carnivores had cascading effects across multiple trophic levels in an intertidal food web, effectively reversing the impacts of mesocarnivore populations on marine biota by markedly suppressing mesocarnivore foraging. Our experimental results corroborate that the existence of large carnivores on the landscape can, in and of itself, provide a critical ecosystem service.


Highlighted Collaborators: Dr. Rudy Boonstra from University of Toronto & Dr. Tony D. Williams from Simon Fraser University

Indirect predator effects on clutch size and the cost of egg production. [PDF]

We directly experimentally demonstrated for the first time in free-living wildlife that losing offspring to predation can reduce the mother’s subsequent fecundity.  Our experimental results established that not just the presence of predators but also the killing they do can cause fear effects on prey fecundity.

Song Sparrow
United Kingdom

Highlighted Collaborator: Dr. David W. Macdonald from the University of Oxford

Fear of the human “super predator” far exceeds the fear of large carnivores in a model mesocarnivore.  [PDF]

Recent worldwide analyses have established that humans, as predators, have a unique ecology that includes disproportionately killing medium and large carnivores, meriting humans being termed a “super predator”.  We experimentally demonstrated for the first time that, consistent with our being far more lethal, we humans inspire far more fear in mesocarnivores than their non-human predators.

European Badger
South Africa

Highlighted Collaborators: Dr. Craig Packer from the University of Minnesota & Dr. Mike Peel from the Agricultural Research Council in South Africa

Fear of the human "super-predator" pervades the South African savanna. [PDF coming soon]

In light of the depletion of their prey due to legal and illegal hunting, and the incidental and intentional killing of lions across Africa, we experimentally tested whether the savanna mammal community now fears the human ‘super predator’ more than the ‘kings of beasts’ (lions), even in one of the continent’s premier protected areas possessing one of the world’s largest lion populations, South Africa’s Greater Kruger National Park. Our results are pressingly pertinent to conservation given that the preservation of African savanna systems relies primarily on photographic tourism, and it is thus essential to understand how fear of humans may impede this, and how this fear may be ameliorated.

Hierarchy of Fear: Experimentally testing ungulate reactions to lion, African wild dog and cheetah. [PDF coming soon]

The fear different large carnivores inspire in intact multi-predator-prey systems may have very different ecological impacts, but research to date has primarily focused on the impacts of one large carnivore at a time. We experimentally tested the relative fearfulness African ungulates demonstrated to playbacks of lions, African wild dogs and cheetahs in South Africa’s Greater Kruger National Park. Our results reveal a very clear ‘hierarchy of fear’, with virtually every ungulate most fearing the ‘kings of beasts’ (lions).

Wildlife (Mammals)
California (USA)

Highlighted Collaborator: Dr. Christopher Wilmers from the University of California

Fear of humans as apex predators has landscape-scale impacts from mountain lions to mice.  [PDF]

We experimentally demonstrated for the first time that a ‘landscape of fear’, resulting solely from variation in perceived predation risk, can have pervasive effects across wildlife communities. Our results established that fear of the human ‘super predator’ can have cascading impacts across multiple trophic levels, suppressing the movement and activity of large carnivores (cougars) and medium-sized carnivores (bobcats, skunks and opossums) alike, with the result that small mammals (mice and woodrats) were free to forage more.

Humans, but not their dogs, displace pumas from their kills: An experimental approach.  [PDF]

We experimentally demonstrated for the first time that large carnivores (cougars) fear hearing human vocalizations more than those of the human commensals (dogs) which are used to hunt them; providing the first indication that whatever the means humans use to hunt them, whether with dogs, guns, or snares, animals may come to learn that it is the presence of the human ‘super predator’ that is the true signal of imminent peril.

Fear of the human ‘super predator’ reduces feeding time in large carnivores.  [PDF]

We experimentally demonstrated for the first time that fear of the human ‘super predator’ can cause a trophic cascade in a large carnivore-ungulate system. Our results established that fear of humans disturbs cougars from their kills (deer), causing cougars to spend less time feeding at each cached deer carcass, thus necessitating their killing more deer per year to compensate, causing a consequent reduction in the consumption of woody vegetation by deer.


Deer Mouse

Georgia (USA)

Highlighted Collaborators: Dr. Michael Conner from The Jones Center at Ichauway & Dr. Michael Cherry from Texas A&M University

Prey tells, large herbivores fear the human ‘super predator’.  [PDF]

Like large and medium-sized carnivores, worldwide analyses have recently shown that large herbivores are killed by the human ‘super predator’ at many times the rate that they are killed by their non-human predators (large carnivores). We experimentally demonstrated for the first time that, as is the case with large and medium-sized carnivores, we humans inspire far more fear in large herbivores (white-tailed deer) than their non-human predators.

White-tailed Deer

Highlighted Collaborators: Dr. Joris Cromsigt from the Swedish University of Agricultural Sciences & Dr. Dries Kuijper from the Polish Academy of Sciences

Playbacks of predator vocalizations reduce crop damage by ungulates.  [PDF]

We experimentally demonstrated for the first time that playbacks of predator vocalizations can provide an effective means of reducing crop damage in agriculture systems. Our results corroborated and expanded our work in Georgia (USA) by showing that multiple large herbivores in Sweden (fallow deer, roe deer, red deer, moose, wild boar) fear hearing humans more than non-human predators, indicating that playbacks of the human ‘super predator’s’ vocalization may be the most effective in reducing crop damage.

Fallow Deer, Roe Deer, Red Deer, Moose, & Wild Boar

Highlighted Collaborator: Dr. Robert A. McCleery from the University of Florida

Fear of large carnivores is tied to ungulate habitat use: evidence from a bifactorial experiment. [PDF]

We experimentally demonstrated for the first time that ungulate habitat selection can be directly linked to their fear of large carnivores, thereby filling a critical gap in the evidence corroborating that the fear of large carnivores can itself cause trophic cascades in large carnivore-ungulate systems.

Wildlife (Mammals)

Highlighted Collaborators: Dr. David W. Macdonald from University of Oxford & Dr. Chris Wilmers from University of California

A new Automated Behavioural Response system to integrate playback experiments into camera trap studies. [PDF]

We experimentally tested the fear wildlife demonstrated to hearing the human ‘super predator’, hunting sounds (dogs barking) and non-human predators (leopards snarling) in Uganda’s Bwindi Impenetrable National Park, in what was one of the first uses of our newly-developed Automated Behavioural Response (ABR) systems. For more details concerning the ABRs please visit the ABR System webpage.

Wildlife (Mammals)

Highlighted Collaborator: Dr. Bart Kempenaers from the Max Planck Institute for Ornithology

Playback of predator calls inhibits and delays dawn singing in a songbird community. [PDF]

We experimentally demonstrated for the first time that fear itself can affect the occurrence and timing of the dawn chorus in songbird communities. Our results established that the impacts of fear can extend to suppressing mating behaviour in free-living wildlife.

Effects of predator call playbacks on reproductive success and extrapair paternity in blue tits. [PDF]

We conducted an experiment on the breeding performance of blue tits which provided a framework for subsequent experiments demonstrating that fear itself can impact extrapair paternity in songbirds.

Blue Tit

Highlighted Collaborator: Dr. Christopher N. Johnson from the University of Tasmania

Fear of the human 'super-predator' 'down-under': Kangaroos and wallabies fear humans more than devils, dogs, and wolves. [PDF coming soon]

We experimentally demonstrated for the first time that even kangaroos and wallabies in Australia fear humans more than non-human predators, corroborating that fear of the human ‘super predator’ is pervasive across the planet.


Highlighted Collaborator: Dr. Dries Kuijper from the Polish Academy of Sciences

We will be initiating new research in Poland’s primeval Białowieża Forest in the summer of 2022, entitled “Are wolves losing their fear of humans? Changes in wolf behaviour and their consequences for prey species in human-dominated landscapes”. [project currently in progress]


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.