Sept. 22 (UPI) — New research suggests animals begin to lose their fear of predators once they start encountering humans on a regular basis.
For the study, scientists surveyed the findings of 173 peer-reviewed papers on predator avoidance behaviors and traits deployed by 102 species of domesticated, captive and urbanized mammals, birds, reptiles, fish and mollusks.
The analysis, published Tuesday in the journal PLOS Biology, showed predator avoidance traits and behaviors, including vigilance, freezing and fleeing, decreased as a result of exposure to humans.
Researchers found individual variation in anti-predator characteristics increased upon a species’ initial exposure to humans, but then gradually decreased after generations of human exposure.