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CONSERVATION
Updated July 25, 2011
Important Landmark 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 Meeteetse,
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. |
