play fighting is often difficult to differentiate from inhibited or immature serious fighting because both may utilize many of the same behavior patterns. In the rat the two behaviors involve different targets of attack. During play fighting, snout or oral contact is directed at the opponent’s nape of the neck, whereas during serious fighting, male residents mostly direct their bites at the intruder’s rump. Although similar to those used in serious fighting, the behavior patterns used during play fighting are modified to achieve the different targets of attack. Even though the tactics of attack and defense appear more adult?like with increasing age, the playful targets persist well into adulthood. Copyright © 1987 Wiley?Liss, Inc., A Wiley Company