International Journal of Comparative Psychology

Ferrets were tested in a free feeding situation that required them to eat only three pieces of food from a randomly sized larger array containing between 15-20 items. Controls were established to preclude discrimination based on spatial or volumetric cues, or cuing by the experimenter. This demonstration represents the first evidence of numerical competence in a mustelid species, and replicates the results of pioneering research by Koehler and his associates with budgerigars (Marold, 1939), as well as more recent work with rats (Davis & Bradford, 1991). Although the performance of ferrets reached comparable levels to those reported with other species, extended training yielded a deterioration in performance. These results are discussed in terms of the role of consequences to suppress competing responses, a problem that has been reported to underlie a variety of learning situations with ferrets.