Back toward the beginning of my Monday Mustelid series I wrote about the Black-footed Ferret, which is native to North America and had suffered such a huge population decline during the 1900s that it was declared extinct before a specimen was discovered in 1981. While concerted captive breeding programs have since generated a wild population of 2,600 Black-footed Ferrets, one of the issues inherent in working with a depleted species is genetic bottlenecks. Each generation, while increasing a species’ numbers, does not necessarily have a corresponding increase in genetic diversity, which can lead to population-wide health problems.

This year, it was demonstrated that using cryopreserved Black-footed Ferret semen harvested 20 years ago could successfully be used to artificially inseminate females generations down the line, increasing the gene pool while at the same time allowing captive breeding programs to produce even more kits. This birth is the first piece of empirical evidence in favor of long-term semen cryopreservation being a viable strategy in restoring populations of endangered animals. This work was done by the Smithsonian National Zoo and Conservation Biology Institute, and they published their work this month.

The Black-footed Ferret who donated this semen about 20 years ago was called Scarface, one of the genetically valuable males that was gathered after the species was rediscovered in 1981. The U.S. Fish and Wildlife Service conducted a thorough search of the area where the initial specimen had been found, which yielded only 18 individuals. Scarface was one of them.

The SCBI had done work in 2008 with cryopreserved semen that was only 10 years old, and successfully impregnated female ferrets who then went on to have offspring and grand offspring. The SCBI worked not only with their own populations of Black-footed Ferrets, but with also with the populations at the following facilities, in conjunction with the AZA’s Species Survival Plan for these ferrets:

  • Cheyenne Mountain Zoo
  • Lincoln Park Zoo
  • Louisville Zoological Garden
  • Phoenix Zoo
  • Toronto Zoo

Footage of some of these very important kits can be viewed here:

More adorable pictures of the kits can be seen here.