Animal Info - Black-footed Ferret

(Other Names: Dlo ii Liz-hinii, Ground Dog, Na-math, Pispiza Etopta Sapa, Putois ŕ Pieds Noirs, Turón Patinegro Americano)

Mustela nigripes

Status: Extinct in the Wild


Contents

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Size and Weight, Habitat, Age to Maturity, Gestation Period, Birth Season, Birth Rate, Early Development, Dispersal, Maximum Reproductive Age, Maximum Age, Diet, Behavior (Activity, Movement, Communication), Social Organization, Age Distribution, Density and Range)
5. References


Profile

Pictures: Black-footed Ferret #1 (19 Kb JPEG) (Mus. Tex. Tech Univ. NSRL); Black-footed Ferret #2 (39 Kb JPEG) (Univ. Kansas); Black-footed Ferret #3 (31 Kb JPEG) (Czech Web Site)

The black-footed ferret weighs about 1 kg (2.2 lb). It is a slender, wiry animal with a black face mask and short, sleek fur with a yellow-buff color. 

The black-footed ferret is usually found on shortgrass and midgrass prairies in close association with prairie dogs, which constitute most of its diet. In addition to feeding on prairie dogs, the ferret lives in prairie dog colonies. It spends most of its time underground in prairie dog burrows, typically spending only a few minutes aboveground each day. In burrows it sleeps, caches its food, avoids predators and harsh weather, and gives birth to its young. While remaining in a burrow the ferret subsists on cached food. The black-footed ferret does not hibernate, but in winter, the amount of time it is active decreases substantially. It is secretive and primarily nocturnal.  

The female black-footed ferret usually bears 3 - 4 young per litter. The young emerge from the burrow in July and leave their mother in September or October. The black-footed ferret is solitary, except during the breeding season, and males apparently do not help to rear the young.

The black-footed ferret originally occurred in the Great Plains from Alberta and Saskatchewan, Canada, to Texas and Arizona, USA. It experienced a dramatic decline during the first half of the 20th century. In Canada, it has not been recorded since 1937. By the late 1970's it was thought to be extinct in both countries. In 1981, however, a colony was found in Wyoming, USA. All remaining black-footed ferrets were captured and sent to a captive breeding center. As a result of the captive breeding program, black-footed ferrets now live at seven reintroduction sites in the USA, including sites in Montana, Wyoming, Arizona, South Dakota, and along the Colorado/Utah border, as well as in Chihuahua, Mexico.

Loss of habitat is the primary reason why the black-footed ferret declined almost to extinction and why it remains severely threatened. Conversion of grasslands to agricultural uses and widespread prairie dog eradication programs have reduced ferret habitat to less than 2 percent of what once existed. Remaining habitat is now fragmented, with prairie dog towns separated by great expanses of cropland and human development. Diseases, including plague (affecting both the ferrets and their prairie dog prey) and canine distemper, as well as poisoning and shooting, also remain as potential threats. 


Tidbits

*** The black-footed ferret is one of the world's rarest mammals.

*** Baby ferrets are called "kits."

*** "They do not appear to be numerous in any part of their range and little is known concerning their habits... With the occupation of the country and the inevitable extinction of the prairie-dog over nearly or quite all of its range, the black-footed ferret is practically certain to disappear with its host species." (Nelson 1918)

*** The ferret's long slender body allows it to slip down burrows to find its prey while they sleep.  This reduces the ferret's risk of injury when attacking prey the same size as itself.

*** Antipathy towards prairie dogs, the black-footed ferret's main source of food, remains prevalent among some groups, including ranchers and many employees of agriculture, wildlife and public land management agencies (Reading 1997).

*** The domestic ferret is a different species (Mustela putorius) from the black-footed ferret. It originated in Europe. (Black-footed Ferret Recov. Prog. 2005) 


Status and Trends

IUCN Status:

  • 1960's - 1994: Endangered
  • 1996 - 2004: Extinct in the Wild (IUCN 2004)

Countries Where the Black-footed Ferret Is Currently Found:

2004: Formerly occurred in Canada and the USA. (IUCN 2004)

Population Estimates:

[Note: Figures given are for wild populations only.]

History of Distribution:

The black-footed ferret originally occurred in the Great Plains from Alberta and Saskatchewan, Canada, to Texas and Arizona, USA. It experienced a dramatic decline during the first half of the 20th century. In Canada, it has not been recorded since 1937. By the late 1970's it was thought to be extinct in both countries.

In the Fall of 1981, however, a colony was found in Meeteetse, Wyoming, USA. A decision was made to capture some animals for breeding purposes in 1985 due to a sharp decline in the wild population. The first group of captured ferrets all died because several were infected in the wild with canine distemper. This led to the discovery that canine distemper was responsible for the rapid decline of the Meeteetse population. At this point, all 18 remaining black-footed ferrets were captured, vaccinated, quarantined, and sent to a captive breeding center. By 1991, the captive population had increased to 311 animals and 49 animals were released into the wild. (Primack 1993)

The captive breeding plan reached its genetic and demographic goals in 1996, and it now manages 240 (90 male and 150 female) breeders. Ferrets in excess of this number are available for reintroduction into suitable habitats. Ferret kits that are destined for release in the wild receive "preconditioning": extended exposure to outdoor pens that have naturalistic prairie dog burrows, and in which developing kits are exposed to prairie dog prey. Preconditioning has significantly enhanced the survival of captive reared ferrets reintroduced into the wild. (Vargas 1999, Black-footed Ferret Recov. Prog. 2005)  

As a result of the captive breeding program, black-footed ferrets now live at seven reintroduction sites in the USA, including Montana (Charles M. Russell National Wildlife Refuge and Fort Belknap Indian Reservation), Wyoming (Shirley Basin), Arizona (Aubrey Valley near the town of Seligman), South Dakota (Badlands National Park and the adjacent Buffalo Gap National Grassland), and along the Colorado (Wolf Creek Management Area located about 20 miles northeast of Rangely)/Utah border, as well as in Chihuahua, Mexico. (Black-footed Ferret Recov. Prog. 2005)

The captive breeding program and reintroduction of ferrets has slowly rebuilt the population to about 500 in the wild  (Focus 2005a)

Distribution Map (historical range) (27 Kb) (NatureServe Expl.) 

Threats and Reasons for Decline:

From the 1920's to the 1960's, the U.S. government sponsored intensive programs to eradicate the prairie dog throughout the Great Plains states by using poison and by plowing under the prairie dog towns (for the purpose of preventing damage to agriculture and cattle ranching). For example, the area occupied by prairie dog towns in Kansas was reduced by 98.6%. The black-footed ferret was apparently an unintentional victim of the prairie dog eradication campaign. Even in the 1990's, federal agencies authorized and subsidized the annual clearing of 80,000 hectares (200,000 acres) of prairie dog colonies. (Caughley & Gunn 1996)

Loss of habitat is the primary reason why the survival of black-footed ferrets remains severely threatened. Conversion of grasslands to agricultural uses and widespread prairie dog eradication programs have reduced ferret habitat to less than 2 percent of what once existed. Remaining habitat is now fragmented, with prairie dog towns separated by great expanses of cropland and human development. Diseases, including plague (affecting both the ferrets and their prairie dog prey) and canine distemper, as well as poisoning and shooting, also remain as potential threats. (Focus 2005a, Black-footed Ferret Recov. Prog. 2005)


Data on Biology and Ecology

Size and Weight:

The black-footed ferret is 46 - 60 cm (18 - 24") long, including a 13 - 15 cm (5 - 6") tail. It weighs 0.7 - 1.1 kg (1.5 - 2.5 lb), with males slightly larger than females. (Black-footed Ferret Recov. Prog. 2005)

Habitat:

The black-footed ferret is usually found on shortgrass and midgrass prairies in close association with prairie dogs. When inactive, it occupies an underground burrow made by a prairie dog.

"Like others of the weasel tribe, [the black-footed ferret] must have a wandering disposition, since one was captured at 9800' [3000 m] altitude, and another was found drowned at 10,250' [3125 m] in Lake Moraine, Colorado [USA]." (Nelson 1918)

Age to Maturity:

Both male and female ferrets become sexually mature at one year of age (Black-footed Ferret Recov. Prog. 2005).

Gestation Period:

41 - 45 days (Hammerson et al./NatureServe 2005, Black-footed Ferret Recov. Prog. 2005).

Birth Season:

Mating generally occurs in March and April. After about 7 weeks, a litter of kits is born. (Black-footed Ferret Recov. Prog. 2005) 

Birth Rate:

The average litter size is 3 - 4 young, but single kits, as well as litters of up to nine or ten kits, have been recorded (Black-footed Ferret Recov. Prog. 2005). In the wild, litter size in South Dakota averaged 3.5 (range 1 - 5) and in Wyoming averaged 3.3 at emergence from the birth burrow (Hammerson et al./NatureServe 2005). The interbirth interval is 1 year (Ferguson & Lariviere 2002).

Early Development:

A black-footed ferret kit is about three-quarters grown by July when it first ventures out of the burrow. Long after it stops nursing, it depends on its mother for meals of meat. By late summer, the female leaves her kits in separate burrows during the day and gathers them together at night to hunt. Eventually, a young ferret begins to hunt alone, and by September or October it is independent and solitary. (Black-footed Ferret Recov. Prog. 2005) 

Dispersal:

A young black-footed ferret leaves its mother in September or early October. Young males then disperse for a considerable distance, generally on the order of 10 - 15 km (6 - 9 mi), but young females often remain in the vicinity of their mother's territory. (Nowak 1999, Hammerson et al./NatureServe 2005) 

Maximum Reproductive Age:

The peak reproductive period of male and female black-footed ferrets lasts about three to four years (Black-footed Ferret Recov. Prog. 2005).

Maximum Age:

Few black-footed ferrets live beyond 3 - 4 years of age (oldest - at least 8 years old) in the wild and 8 - 9 years (oldest - at least 11 years old) in captivity (Ferguson & Lariviere 2002, Black-footed Ferret Recov. Prog. 2005).

Diet:

In the wild, prairie dogs make up 90% of a black-footed ferret's diet. A ferret may eat over 100 prairie dogs in one year, and scientists calculate that over 250 prairie dogs are needed to support one ferret family for one year. The black-footed ferret may also eat ground squirrels, other small rodents, cottontail rabbits and birds. (Black-footed Ferret Recov. Prog. 2005) 

Behavior:

The black-footed ferret is secretive and primarily nocturnal.  It is thought to have keen senses of hearing, smell and sight.

The black-footed ferret is highly dependent on the prairie dog. In addition to feeding on prairie dogs, the ferret lives in prairie dog colonies. It spends most of its time underground in prairie dog burrows, typically spending only a few minutes aboveground each day to hunt or find new burrows or mates. In burrows it sleeps, caches its food, avoids predators and harsh weather, and gives birth to its young. (Caughley & Gunn 1996, Hammerson et al./NatureServe 2005, Black-footed Ferret Recov. Prog. 2005) 

Activity - Most of the black-footed ferret’s daytime activity is limited to the first few hours following sunrise. Males are more active than females. The ferret does not hibernate, but in winter, the amount of time it is active and the distances it travels decrease substantially. In winter the ferret can be inactive for periods of up to 6 nights and days. While remaining in a burrow the ferret subsists on cached food. (Hammerson et al./NatureServe 2005, Black-footed Ferret Recov. Prog. 2005) 

Movement - When aboveground, the black-footed ferret travels in a series of jumps or a slow gallop. It can travel at a rate of 8 - 11 kph (5 - 7 mph). Biologists have tracked ferrets who have traveled 10 km (6 mi) in one night, and one ferret investigated more than 100 prairie dog burrows in one night. Distances traveled by males tend to be about double those of females. (Black-footed Ferret Recov. Prog. 2005) 

Communication - The black-footed ferret is a very vocal animal. It chatters loudly when it is alarmed or excited. At such times, it emits several loud barks interrupted by low hissing sounds. A male ferret "chortles" to a female during breeding, and ferret kits emit tiny squeaking sounds. The black-footed ferret also communicates with scent. It marks its territory by rubbing its scent glands on rocks, soil, and vegetation. (Black-footed Ferret Recov. Prog. 2005) 

Social Organization:

The black-footed ferret is solitary, except during the breeding season or when females are caring for young. Male ferrets play no part in raising the young. (Black-footed Ferret Recov. Prog. 2005) 

Age Distribution:

The wild population near Meeteetse, WY, USA, consisted of 67% juveniles and 33% adults each August (Nowak 1999).

Density and Range:

Investigation of the wild population near Meeteetse, WY, USA, revealed a density of about 1 ferret per 50 ha (125 acres) of prairie dog colonies. The average distance between two prairie dog towns occupied by ferrets was 5.4 km (3.3 mi). (Nowak 1999)  

The home ranges of adult black-footed ferrets have diameters of roughly 1 - 2 km (0.6 - 1.2 mi). It has been estimated that about 40 - 60 ha (100 - 150 acres) of prairie dog colony are needed to support one ferret. A black-footed ferret may range over an area of up to 100 ha (250 acres) during a 3 - 8 day period in winter. (Hammerson et al./NatureServe 2005) 

The ferret is territorial (Black-footed Ferret Recov. Prog. 2005) .


References

Arkive, Berger 1990, Black-footed Ferret Recov. Prog. 2005, Caughley & Gunn 1996, Clark 1976, Ferguson & Lariviere 2002, Focus 2005a, Hammerson et al./NatureServe 2005, IUCN 1968, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Lee 1995, McClung 1969, Mus. Tex. Tech Univ. NSRL, NatureServe Expl., Nelson 1918, Nowak 1999, Nowak & Paradiso 1983, Primack 1993, Reading 1997, Schreiber et al. 1989, Thorne & Williams 1988, Univ. Kansas, Vargas 1999, WCMC et al. 2000 


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