A longitudinal study of dominance in an outdoor colony of domestic rats.

Pre-and postpubertal play soliciting behavior was observed in intact males, castrate males, sham-operated males, and female controls. Although play soliciting decreased markedly with age in all groups, male treatment groups did not differ reliably on pre-or postpubertal tests. Males, however, engaged in reliably greater play soliciting than females on all measures in both preand postpubertal tests. These results suggest that the major decrease in social play associated with the attainment of sexual maturity is apparent in the play soliciting behavior of both sexes and may be attributed to maturation effects other than that associated with gonadal hormones. The results are discussed in reference to organizational and activational effects of male gonadal hormones on measures of social play behavior.

supporting

confidence: 92%

mentioning

confidence: 99%

Play soliciting behavior in prepubertal and postpubertal male rats

Thor¹,

Holloway²

1985

“…A numberof studies have reportedfmdings for rats and micethat are similarto those of this experimentin showing that, comparedwith controlanimals, rats that are exposed to repeated defeat show an increment in defensive and/or submissive responses (e.g., Frischknecht et al, 1982;Kulling et al, 1987;Seward, 1946) and a reduction in body weight (Adams & Boice, 1983;Luciano & Lore, 1975;Raabet al, 1986;Thor & Flannelly, 1976). The results of the present study also indicate that the amount of time that was engaged in defensive behavior is negatively correlated with the amount of weight that was gained by the defeated rats, which suggests that intruder defeat is a stressfulevent that has both behavioral and physiological consequences.…”

Section: Discussionsupporting

confidence: 73%

“…This type of natural stressor also decreases subsequent exploratory behavior and increases freezing (e.g., Raab et al, 1986). Finally, repeated defeat by conspecifics produces many of the physiological changesthat also occur as a result of shockinduced learned helplessness, such as weight loss (e.g., Adams & Boice, 1983;Luciano & Lore, 1975;Thor & Flannelly, 1976;Raab et al, 1986), endocrine changes (e.g., Raab et al, 1986), and analgesia that is mediated by endogenous opioid mechanisms (e.g., Miczek, Thompson, & Shuster, 1982, 1986Rodgers& Randall, 1986b) and nonopioid mechanisms (McAllister, Berry, & Brain, 1985;Rodgers & Randall, 1986a).…”

mentioning

confidence: 99%

Effects of repeated defeat by a dominant conspecific on subsequent pain sensitivity, open-field activity, and escape learning

Williams

Lierle

1988

Male rats were tested as intruders for 25 consecutive days in colonies that had either aggressive (i.e., alpha) or nonaggressive conspecific residents. Alpha-defeated intruders, in contrast to nondefeated rats, showed more defensive behavior, less gain in body weight, and received more bites during the course of these sessions. Tail-flick tests, using a heat source, revealed that both groups of intruders showed comparable sensitivity/reactivity to pain, and there was no evidence of analgesia as a function of resident encounters. Immediately after the last intruder session, all subjects were tested for exploratory activity in an open-field apparatus with the odors (i.e., soiled bedding) from the alpha colonies present. Defeated intruders showed significantly less locomotion, in terms of the number of grid crossings, than nondefeated rats. Twenty-four hours later, randomly selected subgroups of defeated and nondefeated subjects were briefly exposed, without being defeated, to aggressive colonies, and all rats were then retested for activity with alpha odors present. Previously defeated intruders were again less active, and the colony-exposure treatment suppressed the activity of defeated, but not nondefeated, subjects. Finally, 24 h after another resident-intruder session, both groups of intruders showed comparable FR 1 escape performance in a shuttlebox with alpha odors present, but the defeated rats failed to learn a subsequent FR 2 escape task. The findings of this experiment are discussed in terms of the concept of "learned helplessness," the effects of ethological stressors, and the authors' stress-coping-fear-defense (SCFD) theory.Numerous investigators have shown that repeated exposure to a laboratory stressor, such as electric shock, produces alterations in behavioral and neurophysiological processes. In mice and rats, experiencing inescapable shock has been shown to interfere with the subsequent acquisition of escape responses (e.g., Anisman, Suissa,

“…Adams and Boice (1983) observed unequivocal dominance relationships based upon threats, attacks, and submission in a developing colony of albino rats living in a large outdoor pen. This finding was replicated and extended to a colony living in an indoor enclosure; however, colonies living in laboratory cages were not found to establish dominance relationships across a 6-month period (Adams & Boice, 1984).…”

mentioning

confidence: 93%

Establishment of dominance in domestic Norway rats: Effects of the degree of captivity and social experience

Adams

1985

Self Cite

The effect of the level of captivity and prior social experience on the establishment of dominance was examined in 16 colonies of albino rats. Males were assigned to one of four treatment groups: aggressive experience, defeat experience, exposure to electric shock, and controls. Following treatment, colonies of four males were established for 12 days in one of three different captive setings: a large outdoor pen, an indoor pen, or laboratory group cages. Effects of treatment were minimal; however, the degree of captivity significantly affected the display of aggression and the establishment of dominance relationships. In the two pen settings, attacks were more frequent and dominance relationships were established in six of eight colonies. Attacks in the laboratory cages occurred almost exclusively during the first 2 days, and no dominance relationships were established in any of eight laboratory cage colonies.