In 1981, scientists found only one small wild population of Black-footed Ferrets in Wyoming. Wildlife organizations, including zoos, have since brought this critically endangered species back from just 18 individuals to more than 2,600 in the wild today. This summer, the Smithsonian Conservation Biology Institute (SCBI) broke the genetic bottleneck facing the species by using semen that had been cryopreserved for 10 to 20 years to artificially inseminate live female ferrets. This breakthrough will increase the number of black-footed ferrets born in human care while enhancing genetic diversity within the species.
The United States Fish and Wildlife Service (USFWS) developed and oversees the Black-footed Ferret Recovery Program. The Association of Zoos and Aquariums’ Species Survival Plan (SSP) manages the Black-footed Ferret breeding program with a breeding population composed of about 300 animals. For this study, all the males were managed either at SCBI or at the USFWS National Black-Footed Ferret Conservation Center. Scientists collected semen samples from adult Black-footed Ferrets that ranged in age from one to six years old. All females were solely managed at SCBI.
Initially, scientists used fresh semen to artificially inseminate females who failed to naturally mate with males, resulting in 135 kits. With just a few founders to rebuild an entire species, early managers of the Black-footed Ferret recovery program knew that genetic diversity could be lost. Loss of genetic variation can lead to increased sperm malformation and lower success of pregnancy over time. Researchers routinely collected and preserved Black-footed Ferret semen for later use as part of standard operating procedures.
Read more about Black-footed Ferret breeding and see more photos below.