The black-footed ferret is an alert, agile, nocturnal animal, which spends the day in prairie dog burrows (7). More than 90 percent of the diet consists of prairie dogs, which are attacked whilst they sleep in their burrows (3), although mice, ground squirrels, voles and other small mammals are also taken (6). This species is solitary, except during the breeding season, which runs from March to April (6). Females give birth to litters of between three to six young (known as kits), and rear their offspring without help from the male. The young, which are born blind and helpless and covered with thin white hair (3), stay in the burrow for about 42 days before venturing above ground, and remain with their mother until the autumn, after which time they disperse (6). These ferrets have excellent senses of hearing, sight and smell, and olfactory communication (urination and defecation) is very important in the maintenance of dominance hierarchies and following trails at night (6). Vocalisations include chattering and hissing (6).