Wild ferrets, America's most endangered mammal, recover
August 9, 2007

Black-footed ferrets (Mustela nigripes), North America's most endangered mammal species, are recovering in their native Wyoming, reports a study published in the current issue of the journal Science.

The wild population of the carnivores was down to seven when they were captured for a captive breeding program in 1981. More than 220 captive-born ferrets were reintroduced into their natural habitat between 1991 and 1994, but disease reduced the population to five by 1997. Nevertheless, continued efforts are paying off and today there are more than 223 ferrets in the wild.

The researchers, led by Martin Grenier of the University of Wyoming in Laramie, say the population recovery is notable "because the bottleneck of the 1980s reduced genetic variability and captive breeding affected various phenotypic traits."

Shirley Basin was the first reintroduction site to release the black-footed ferret in 1991. The reintroduced population persisted at low levels in Shirley Basin, Wyoming for several years, but is now experiencing rapid population growth. [Image and caption courtesy of LuRay Parker, Wyoming Game and Fish Department.
Grenier and colleagues are hopeful that the recovery can continue despite its inauspicious beginnings.

"Although some attempts may not yield immediate success, the Shirley Basin example shows that species recovery is possible, given the ferret's capacity to persist at low population levels and to increase rapidly in favorable environments," the authors write, adding that survival of young ferrets is critical to the population health of the species.

CITATION: M.B. Grenier, D.B. McDonald and S.W. Buskirk (2007). "Rapid Population Growth of a Critically Endangered Carnivore. 10 AUGUST 2007 VOL 317 SCIENCE.


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Wild ferrets, America's most endangered mammal, recover.