IN BECENT YEABS a number of investigations have demonstrated the existence, in mammals, of behaviour not motivated by fear, thirst, or hunger, and unrelated to general activity level. These have led to the postulation of another drive-the exploratory drive. Characteristically, such behaviour is aroused by novel external stimulation; it involves either locomotor activity or manipulation of objects, and it declines as a function of tune. Studies in which the relative complexity of the environment was varied have shown that rats and chimpanzees prefer more complex and novel situations to less stimulating ones ( 7,8,21,22,23). Fear (13,14), hunger (1,11,19), peripheral blindness (4), and restriction (12, 20) have also been utilized as independent variables; the effects of the first three on exploratory behaviour have been studied in rats, and the effect of restriction has been investigated in both rats and dogs. Further proof that exploration operates as an independent drive is furnished by the experiments of Butler (3) and Montgomery and Segal! (15) which showed that exploration could be effectively utilized as an incentive to learning.The present study was undertaken in an attempt to obtain some measures of exploration in a previously uninvestigated species, the blackfooted ferret (musteUa nigripes). These animals, when adult, measure approximately 20 in. from head to tail and have long, slim bodies, short legs, and pointed noses. They belong to the Musteldae family, other members of which include the mink, weasel, and marten (16).
METHOD
SubjectsThe subjects were 6 tame, experimentally naive, adult ferrets, which were obtained from a local mink breeder who had reared them from infancy in outdoor pens. At the time of testing, the 5 females were about 1 yr. of age, and the male was 2 yr, of age. In the laboratory, they were housed in individual wire-mesh cages measuring 12 in. X 12 in. X i2 m. and were fed one meal per day consisting of 31 lb. of canned dog food mixed with powdered milk; water was available at all times. It should be noted that 24 far. often passed before the full ration was consumed; that is, the animals were virtually on an ad lib. schedule.