Black-Footed Ferrets Born at the Smithsonian’s National Zoo and Conservation Biology Institute

Carnivore keepers at the Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) in Front Royal, Virginia, welcomed a litter of endangered black-footed ferrets this week. One-year-old female Aristides gave birth to six kits May 11. Animal care staff are closely monitoring the ferrets’ behaviors through the Black-Footed Ferret Cam, a temporary live webcam on the NZCBI website.  

Starting at four days old, the kits receive regular check-ups to ensure they are developing normally and gaining weight appropriately. When the kits are about 10 days old, animal care staff will perform a neonatal exam and determine their sexes. 

This is the second litter for Aristides, who was born at the Louisville Zoo, and the third for 2-year-old male Thanos, who came to NZCBI from the Phoenix Zoo. Both Aristides and Thanos produced litters at NZCBI last year. Aristides and Thanos received a breeding recommendation from the Association of Zoos and Aquariums’ Saving Animals From Extinction (SAFE) program. SAFE tracks the lineage of individual animals in a record called a “studbook.” When considering which animals to breed, a studbook keeper examines the individuals’ genetic relatedness to one another, overall health and temperament, among other factors, and makes recommendations accordingly. This matchmaking process helps ensure the genetic diversity of a population in human care. Aristides is one of 19 breeding female black-footed ferrets residing at NZCBI. Paul Marinari, senior curator of animal care sciences at NZCBI, is the studbook keeper for black-footed ferrets. 

At birth, black-footed ferret kits are blind, weigh less than 10 grams and have a thin layer of white fur covering their bodies. Their signature mask-like markings around their eyes and dark markings on their feet will appear when they are about 3 weeks old. They will open their eyes at around 37 days old. Between 45 to 50 days old, kits will begin venturing out of their den and exploring the tunnel systems in their enclosures that mimic the prairie dog burrows in which black-footed ferrets live in the wild. 

The kits will nurse for about a month before sampling from their mom’s diet and eating meat. Around 3-to-4 months old, the kits will separate from their mother. The SAFE Black-Footed Ferret program will conduct a genetic assessment of the entire black-footed ferret population managed in human care in August. This assessment will determine whether the kits will remain at NZCBI, transfer to another breeding facility or join the U.S. Fish and Wildlife Service (USFWS) pre-conditioning program in preparation for their release into the wild. The pre-conditioning program allows ferrets to learn to live in burrows and show they can successfully catch prey before being reintroduced to the wild. 

Black-footed ferrets are North America’s only native ferrets. The species was presumed to be extinct until 1981, when the last colony was found near Meeteetse, Wyoming. USFWS and the Wyoming Game Department brought 18 black-footed ferrets into human care. Since 1989, NZCBI has participated in a cooperative breeding program. 1,218 kits have been born at NZCBI, with over 750 ferrets reintroduced to the wild. Currently, 48 black-footed ferrets live at NZCBI.  

The Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) leads the Smithsonian’s global effort to save species, better understand ecosystems and train future generations of conservationists. Its two campuses are home to some of the world’s most critically endangered species. Always free of charge, the Zoo’s 163-acre park in the heart of Washington, D.C., features 2,100 animals representing 400 species and is a popular destination for children and families. At the Conservation Biology Institute’s 3,200-acre campus in Virginia, breeding and veterinary research on 250 animals representing 20 species provide critical data for the management of animals in human care and valuable insights for the conservation of wild populations. NZCBI’s more than 300 staff and scientists work in Washington, D.C., Virginia, and with partners at field sites across the United States and in more than 30 countries to save wildlife, collaborate with communities, and conserve native habitats. NZCBI is a long-standing accredited member of the Association of Zoos and Aquariums.  

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Photo caption: The Zoo welcomed three litters of black-footed ferret kits, including those born to Aristides (above). Photo credit: Smithsonian’s National Zoo and Conservation Biology Institute