Ferrets are the domesticated form of the European polecat. Changes in ferret kit, face to face orientation (en face) were described for littermate dyads at 46, 62, and 94 days after birth. En face characteristics were discussed in terms of their appropriateness for reported burrow attachment and subsequent dispersal of polecat kits to illustrate both the transactional and the developmental nature of our approach and to emphasize the neglected developmental problem of knowing the organization of kit behavior in its ecological setting. This emphasis brings into question the appropriateness of play criteria, reduces the heuristic value of play for those interested in development, and suggests the importance of multiple endpoints for developmental investigations. Play also limits developmental investigations because of the nature of ethological behavioral categories: Their adult, motivational, and evolutionary emphases direct attention to “functional” rather than “analytic” questions. Although these questions are complementary, they are not equally appropriate for problems of evolution and development because the former direct our attention of behavior of young organisms while the latter direct our attention to mechanisms of the developmental process. Our evaluation of play applies equally well to other functional categories of behavior, such as sexual and aggressive behavior.