The study by Wildlife Conservation Society scientist Joel Berger found that when such familiar predators are removed, fear disappears -- a critical piece of knowledge as biologists and public agencies re-introduce large carnivores to places in which they have been exterminated.
Berger notes the goal of re-introduction isn't simply to save a species; it's to restore the natural functions of wild places. When predator-prey relationships come back into balance, impacts ripple through the system.
For example, when wolves returned to the Yellowstone region, they caused a cascade of events including more wariness in moose and changes in elk distribution and coyote densities.
"It's not just changes in climate or disease that may alter our big remote wild landscapes, but so do the actions of conservationists and public agencies by restoring ecosystems to bring native carnivores back to where they once thrived," said Berger.
The study, which looked at 19 areas -- including the Russian Far East, Greenland, Canada and the United States -- is reported in the latest issue of the journal Conservation Biology.