Effect of Domestication on Aggression in Gray Norway Rats

Abstract

A comparative analysis of intermale aggression in the resident-intruder test was conducted with gray rats from a wild unselected population bred at the laboratory for three generations and gray rats selected for elimination (tame) and enhancement (aggressive) of aggressiveness towards human for 71-72 generations. Males from the laboratory line Wistar were used as neutral opponents. Rats from the tame line were characterized by reduced aggression manifest as longer attack latency, decreased number of attacks, upright postures, chases, kicks, and shorter total time of aggressive behavior compared to unselected males. There was no significant difference in the attack latency and the total time of aggression between rats of the aggressive line and unselected rats. A trend to decrease in the number of attacks, chases and upright postures and to increase in contribution of lateral threat postures to the total time of aggression was observed for males of the aggressive line. Plasma corticosterone in unselected males not presented with intruders and after their presentation was higher than in males of both selected lines. Comparative behavioral analysis of agonistic behaviors in rats from the aggressive and tame lines to opponents of different lines (Wistar, tame, aggressive) showed that the presence of an intruder from the aggressive line can enhance aggressive responses in residents from the tame line. Thus, selection for domestication of gray rats caused a significant attenuation of aggressive behavior without affecting the basic agonistic repertoire.

Escalation of cocaine self-administration in adulthood after social defeat of adolescent rats: role of social experience and adaptive coping behavior

“…A trained observer (intra-observer reliability r>0.93) measured previously described intruder and resident behaviors (Buwalda et al 2013; Koolhaas et al 1980; Plyusnina et al 2011) during separate observations. Non-social exploration (walking, rearing, and sniffing) and non-ambulatory motor behavior were quantified for all rats.…”

Domestication and early experiences in chickens: Behavior, stress and gene expression

“…The molecular basis of the stress response Attenuation of the stress response is a well-known trait of the domestic phenotype (Ericsson et al, 2014;Gulevich et al, 2004;Künzl and Sachser, 1999;Plyusnina et al, 2011;Trut et al, 2009;Weiler et al, 1998). By investigating gene expression on various levels of the HPA axis in ancestral and domesticated chickens, we have discovered a number of genes differing in expression between these two breeds.…”

“…Domesticated species show an attenuated stress response both behaviorally and physiologically (Ericsson et al, 2014;Gulevich et al, 2004;Künzl and Sachser, 1999;Plyusnina et al, 2011;Trut et al, 2009;Weiler et al, 1998). This effect of domestication is thought to be an adaptation to the captive environment combined with selection pressure for higher reproductive capacity.…”

Effects of Activation and Blockade of Serotonin 5-HT1A Receptors on the Immune Response in Rats Selected for Different Levels of Aggressiveness

“…Point scales for defensive responses of both lines of rats from 2 to 3 months of age were based on the "glove test" [25] [33] [34] [37].…”

“…The level of aggressiveness was measured in the "glove test" by confronting rats of both lines with an ap-proaching human hand and attempting to handle them [25] [33] [34] [37]. The intensity of response to handling was evaluated according to the following five-score system: 0-rat permits to handle and does not make any attempts of avoiding; 1-permits to handle and makes evasive movements in the hand; 2-moves away from the hand and while being picked up tries to break loose; 3-actively escapes handling and while being picked up, rat can emit loud screaming noises, opens mouth or bites; 4-rat does not permit to handle, attacks the hand and emits loud screaming noises.…”