In a “rewilding” movement cheered by some but decried by others, wolves have recolonized portions of their former range in the United States.

Red wolf (Canis rufus)reintroduction was among the first instances of a species, considered extinct in the wild, being re-established from a captive population. In many ways the red wolf program was the pilot program, serving as a model for subsequent canid reintroductions, particularly those of the Mexican gray wolf (Canis lupus baileyi) to the American Southwest and the gray wolf (Canis lupus) to the Yellowstone region.

But what opportunities do we have to expand the rewilding effort?

A new study published Wednesday in Royal Society Open Science is the first to provide a spatially explicit global assessment of future large carnivore rewilding possibilities.

The paper mentions just two specific sites where further wolf reintroductions might work. They suggest it could be possible to put gray wolves in Olympic National Park in Washington and restore critically endangered red wolves into Everglades National Park. These places have space for reproduction and development, prey and humans who may tolerate them.

More: ‘Rewilding’ Missing Carnivores May Help Restore Some Landscapes via The New York Times