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Wild animals quickly lose their fear of predators after they start meeting humans

Wildlife cyclist

Many wild animals quickly lose their fear of predators after starting to encounter humans.

Most wildlife exhibits a range of predator avoidance behaviors such as vigilance, freezing, and running away. But these are rapidly reduced after animals come into contact with humans through captivity, domestication or urbanization, according to a study by Benjamin Geffroy of MARBEC (Institute of Marine Biodiversity, Exploitation and Conservation), published on September 22, 2020, in the open access magazine PLOS biology.

The international team of researchers analyzed the results of 1

73 peer-reviewed studies investigating anti-predatory traits (behavioral and physiological) in 102 domesticated, captive and urbanized mammal, bird, reptile, fish and shellfish species, taking into account their location. in the Tree of Life.

Urbanized Nubian Ibex

An “urbanized” Nubian ibex (Capra nubiana) tolerating a close human approach in the city of Mitzpe Ramon, Israel. Credit: Adi Einav, 2020

Scientists found that contact with humans led to a rapid loss of the animals’ anti-predatory traits, but at the same time the variability between individuals initially increases and then gradually decreases over the generations in contact with humans. The authors speculate that this two-step process is caused by the reduced pressure of natural selection due to living in a safer environment, followed by artificial selection by humans for docility in the event of domestication.

The animals showed immediate changes in antipredator responses in the first generation after contact with humans, suggesting that the initial response is a result of behavioral flexibility, which may later be accompanied by genetic changes if contact continues for many generations. The researchers also found that domestication altered the animals’ anti-predator responses three times faster than urbanization, while captivity brought about the slowest changes. The results also showed that herbivores changed behavior more rapidly than carnivores, and that solitary species tended to change more rapidly than animals living in groups.

The study shows that domestication and urbanization put similar pressures on animals and can cause rapid behavioral changes. Loss of anti-predatory behavior can cause problems when those domestic or urbanized species encounter predators or when captive animals are released back into the wild. Understanding how animals respond to contact with humans has important implications for conservation and urban planning, captive breeding programs, and livestock management.

Dr Geffroy adds: “Although being protected from humans is known to diminish anti-predatory abilities in animals, we did not know how quickly this happened and to what extent this compares between contexts! We also integrated physiological traits into the study, but they were far fewer in number than behavioral traits. We believe they should be systematically studied to draw a global model of what is happening at the individual level. More data is needed to understand if this happens even with the mere presence of tourists “.

Reference: “Evolutionary dynamics in the Anthropocene: History of life and intensity of the anti-predatory responses of the form of human contact” by Benjamin Geffroy, Bastien Sadoul, Breanna J. Putman, Oded Berger-Tal, László Zsolt Garamszegi, Anders Pape Møller and Daniel T . Blumstein, 22 September 2020, PLOS biology.
DOI: 10.1371 / journal.pbio.3000818

Funding: DTB is supported by the National Science Foundation and the Australian Research Council. But the funders played no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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