Updated July 25, 2011
Reached in Black-footed Ferret Recovery
by Guy Graves, Conservation Keeper
With the birth of 39 Black-footed ferret kits at the Louisville Zoo’s Conservation Center, the total number of young produced since the inception of the program in 1991 is 876. This, coincidentally, is just shy of the number of Black-footed ferrets believed to exist in the wild, and is a result of a 30 year combined effort by federal and state agencies and zoos to reintroduce this endangered animal to its historical homeland of the western plains of the United States, Canada, and Mexico.
The Black-footed ferret is the North American relative of the ferret that people sometimes keep as pets, the European polecat. Our native ferret once ranged from Southern Canada to Northern Mexico across the western plains states where it preyed on its primary food source, prairie dog. Widespread poisoning of prairie dogs diluted the ferrets’ food supply and as a result, the numbers of Black-footed ferrets dwindled to the point that they were thought to be extinct as recently as 1980. A last wild population of about 120 animals was discovered near e, Wyoming, and these animals were studied in the wild until 1985 when a possible distemper outbreak reduced their number to just 18. These last 18 Black-footed ferrets were taken into captivity and placed in quarantine at the National Black-footed ferret Conservation Center. The long-term goal of taking the animals into captivity was to breed them and release their offspring into suitable prairie habitat in an effort to reintroduce the species back into the wild.
Zoos were enlisted to help with the contingency that the ferrets be housed in a quarantine environment to protect them from canine distemper, which is fatal to ferrets. The Louisville Zoo opened its Conservation Center in January of 1991 and became one of five zoos to take part in the recovery project.
The Louisville Zoo’s Conservation Center started with twelve ferrets in 1991 and has maintained a population of around thirty animals in the years since. The ferrets are housed by themselves and a single male is exposed to a female during the breeding season to mimic the solitary existence of these animals in the wild. A litter of 1-10 young or “kits” is born after a 42 day gestation. The young ferrets grow rapidly and are given prairie dog meat beginning at 50 days of age. At around 90 days of age, the young kits that will be released leave Louisville for a preconditioning pen at the National Black-footed Ferret Conservation Center in Carr, Colorado. These pens are operated by the U.S. Fish and Wildlife Service and are basically enclosed prairie dog habitats where the ferrets are released to verify that they are able to hunt prairie dogs and support themselves. The ferrets then leave the preconditioning facility and are released onto one of 19 release sites across the U.S., Canada, and Mexico.
Each year, some of the kits produced at each captive breeding center are retained in the program to replace older animals that have reached the end of their reproductive years. These older ferrets are then placed in education exhibits, such as the one in the Zoo’s MetaZoo Education Center.
Overall, the combination of the zoos and the National Black-footed Ferret Conservation Center has produced over 7,000 kits from the original 18 animals and their descendents. There are currently around 1,000 black-footed ferrets in the wild, with 350 in captivity in the breeding centers. 2011 is the 30th anniversary of the rediscovery of the last wild population of Black-footed ferrets, and the 20th anniversary of the start of the Louisville Zoo’s involvement with the program. We have come a long way in that time, but there is still a long way to go to ensure a future for the Black-footed Ferrets.