Differential rates of attack, defense, and counterattack during the developmental decrease in play fighting by male and female rats

Abstract

During postweaning development, rats exhibit several well documented trends in their play fighting: (1) It peaks between 30-40 days and then declines with the approach of sexual maturity; (2) males initiate more play fights than females; and (3) the overall complexity of play fights, as expressed by such measures as duration of bouts, also decreases with increasing age. Such trends could arise from changes in attack or defense, or some combination of both. In this article it is shown that (a) the decline in play fighting with the onset of sexual maturity in rats results from a decline in attack, not in defense; (b) the differences in play fighting by male and female rats are due to sex-specific rates of both attack and defense; and (c) the developmental decrease in the complexity of play fighting arises from a decrease in the frequency of counterattacks (i.e., after an animal defends itself, it is less likely to launch an attack). In this way, age and sex differences in play fighting can be traced to differences in its subcomponents.

Social interactions in adolescent and adult Sprague–Dawley rats: Impact of social deprivation and test context familiarity

“…These findings contrast with data from Johnston and File [14] who found that hooded Lister female rats did not increase their social activity when examined in a familiar test situation. Similarly, whereas we observed comparable levels of play fighting in adolescent males and females, some sex differences in components of social interactions have been reported previously among adolescents [21,25,26,32,33], with adolescent males, for instance, engaging in more play fighting [32,33]. Although no main effects or interactions involving sex emerged in overall ANOVAs for each measure of social behavior, social motivation, and locomotor activity, it is possible that the pronounced effects of housing conditions, test situation, and age, as well as interactions of these three factors could have masked possible sex-related differences.…”

Social reward-conditioned place preference: A model revealing an interaction between cocaine and social context rewards in rats

“…Douglas et al (2004) reported that although both male and female adolescents demonstrate social reward-CPP, the effect is most pronounced among the isolation-housed males. In addition, a number of studies have shown that males generally engage in more play and other dominance-related behaviors than females (Douglas et al, 2004;Meaney & Stewart, 1981;Pellis et al, 1997;Pellis & Pellis, 1990;Thor & Holloway, 1983. Given that Douglas et al included both sexes in their correlation analyses, whereas the present study did not include females, it is possible that females may have contributed to the positive correlations observed previously.…”

The role of androgen receptors in the masculinization of brain and behavior: What we've learned from the testicular feminization mutation

“…In rats, play fighting, also called rough-and-tumble play, peaks between postnatal days 30-40 (Thor and Holloway, 1984), and occurs more frequently in males than females (Olioff and Stewart, 1978;Pellis and Pellis, 1990). Play fighting is decreased in male rats castrated at birth and its frequency begins to decline at the onset of puberty (Beatty et al, 1981;Meaney, 1988;Pellis and Pellis, 1990).…”

“…In rats, play fighting, also called rough-and-tumble play, peaks between postnatal days 30-40 (Thor and Holloway, 1984), and occurs more frequently in males than females (Olioff and Stewart, 1978;Pellis and Pellis, 1990). Play fighting is decreased in male rats castrated at birth and its frequency begins to decline at the onset of puberty (Beatty et al, 1981;Meaney, 1988;Pellis and Pellis, 1990). Analysis of Tfm male rats suggests that ARs are involved in the development of play fighting behavior since, as juveniles, Tfm males show decreased play fighting behavior compared to wt males (Meaney et al, 1983;Meaney, 1988), although recent data suggest that this difference may depend on the testing paradigm (Field et al, 2006).…”