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all black and it has a shorter neck and shorter ears.
Habit
Black-footed ferrets would not be readily observed even if they were common. They are primarily nocturnal, with most daytime activity limited to the first few hours following sunrise. They spend most of their time in underground burrows, typically spending only a few minutes above ground each day. Finally, ferrets occur in areas with low human densities, also making observation difficult.
Ferrets do not hibernate, but in winter, the distances traveled and the amount of time they are active decrease substantially. Ferrets have been found to remain underground in the same burrow system for a week at a time in winter. In contrast, ferrets have been observed traveling more than four miles in one night in September. Distances traveled by males tend to be about double that of females.
Black-footed ferrets can be playful, especially as juveniles. Young at play will wrestle, arch their backs and hop on their toes and hop backward.
Vocalizations are used for various purposes by black-footed ferrets. A chatter or hiss is used as an alarm call, and whimpering sounds are used by females to encourage young to follow.
Reproduction
Black-footed ferrets lead solitary lives except during the breeding season and when females are caring for young. Breeding activity generally occurs in March and April, and after a gestation period of 41 to 45 days, a litter, typically three or four young, is born.
Young are born blind and helpless, but development is fairly rapid. Young are about three-quarters grown in July when they first venture above ground. Only the females care for the young, which continue to receive food for about a month after weaning. By August, the young begin hunting alone and by September they are independent. Both male and female ferrets become sexually mature at one year of age, and their peak reproductive period appears to be about three to four years.
Food
The black-footed ferret is a predator, and the bulk of the its diet naturally consists of animals. Since ferrets are closely associated with prairie dogs, it is not surprising that close to 90 percent of their diet is prairie dogs. The remainder of the diet includes mice, ground squirrels, rabbits, rats, birds and even reptiles and insects.
Ferrets have a high metabolic rate and require large quantities of food in proportion to their body size. Food requirements vary seasonally and among individual ferrets, but captive ferrets have been found to consume one prairie dog every three or four days. Based on the caloric needs of black-footed ferrets in captivity, the number of prairie dogs and the acreage of prairie dogs needed to sustain individuals and family groups of ferrets has been calculated.
The black-footed ferret, like other members of the weasel family, kills by attacking its prey at the neck and base of the skull. Since prairie dogs are about the size of a ferret, a struggle often ensues when prairie dogs are attacked.
As with most predators, black-footed ferrets are opportunistic in their feeding behavior. They cache prairie dogs to feed on at a later time, and they feed on carrion.
Ferrets may reduce prairie dog numbers in small colonies by predation and by the disruption of prairie dog breeding activity caused by their presence in a prairie dog colony. Studies have shown a decline in prairie dog numbers in a part of a colony occupied by ferrets, but the total number of prairie dogs in the colony was not greatly affected.
Black-footed ferrets are closely associated with prairie dogs found in short and mid-grass prairies of the Great Plains. They use prairie dogs for food, and use the burrow systems for shelter and for raising young. During nine years of study in South Dakota in the 1970s and four years in Wyoming in the early 1980s, ferret litters were found only in prairie dog colonies. Individual ferrets have been found outside prairie dog colonies during periods of dispersal, however.
Loss of habitat is the primary reason black-footed ferrets remain at the brink of extinction. Conversion of rangeland to agricultural and other uses, and prairie dog eradication programs have reduced ferret habitat to a small fraction of what once existed. Remaining ferret habitat is now fragmented, with prairie dog towns separated by large expanses of cropland and grassland unoccupied by prairie dogs. Some ferrets undoubtedly have died from eating prairie dogs that died or were dying from consuming poisoned grain distributed to eradicate prairie dogs.
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