The social life of Norway rats (Rattus norvegicus)

Abstract

The Norway rat has important impacts on our life. They are amongst the most used research subjects, resulting in ground-breaking advances. At the same time, wild rats live in close association with us, leading to various adverse interactions. In face of this relevance, it is surprising how little is known about their natural behaviour. While recent laboratory studies revealed their complex social skills, little is known about their social behaviour in the wild. An integration of these different scientific approaches is crucial to understand their social life, which will enable us to design more valid research paradigms, develop more effective management strategies, and to provide better welfare standards. Hence, I first summarise the literature on their natural social behaviour. Second, I provide an overview of recent developments concerning their social cognition. Third, I illustrate why an integration of these areas would be beneficial to optimise our interactions with them.

Wistar rats and C57BL/6J mice differ in their motivation to seek social interaction versus food in the Social versus Food Preference Test

“…To establish the Social versus Food Preference Test and characterize how manipulating the internal motivational drives for social interaction-seeking and food-seeking behavior affects behavior in this test, we tested how subjects' preference to investigate a social stimulus (novel age-and sex-matched conspecific) versus a food stimulus (standard laboratory chow) was modulated by social isolation and hunger. In Experiment 1a the subjects were adolescent (39)(40)(41)(42)(43)(44)(45)(46) day old) Wistar rats (8 males/6 females; 1 male was subsequently removed from all analyses due to escaping the testing apparatus), and in Experiment 1b the subjects were a separate cohort of adult (13)(14) week old) Wistar rats (8 males/8 females). In both experiments, subjects were first habituated to the testing apparatus as described above, and then tested in the Social versus food Preference Test at zeitgeber time (ZT) 12 on four occasions each 48 hrs apart using a withinsubjects 2 x 2 counterbalanced design (pair-housed/socially isolated x sated/food-deprived).…”

“…It should be noted, however, that the minimum amount of social isolation examined in this meta-analysis (48 hr) was at least twice that used in our current study (24 hrs in rats, 18 hrs in mice). A social isolation-induced increase in food-directed motivation may be an adaptive response since socially isolated subjects are unable to engage in huddling, a behavior commonly expressed by rats and mice [39][40][41] and which is thought to serve a thermoregulatory purpose [42]. Thus, these long-term socially isolated subjects may have had increased metabolic demands that manifested as increased food-directed motivation.…”

Female rat sexual behavior is unaffected by perinatal fluoxetine exposure

“…A limitation of the previous studies was the use of traditional test set-ups in which rats have a limited amount of both space and time to interact with each other. In addition, the use of only pairs of rats limits the opportunity to explore social interaction and does not model the natural situation in which rats live in groups (Calhoun, 1963;Robitaille and Bovet, 1976;Schweinfurth, 2020). In nature, rats copulate in groups consisting of one or several females and males (Calhoun, 1963;Robitaille and Bovet, 1976), and the mating patterns in groups of rats are quite different from the mating patterns observed in the traditional laboratory mating tests with pairs of rats or mice Agmo, 2014, 2015b;Garey et al, 2002;McClintock, 1984;McClintock and Adler, 1978;Snoeren et al, 2015).…”

Novel Competition test for food rewards reveals stable dominance status in adult male rats

“…Integrative cross-species approaches are crucial in the understanding of the roots of social behavior and in the identification of the proximal and neural mechanisms of how we perceive, compute and react upon social information (Keysers and Gazzola, 2016; Schweinfurth, 2020). Norway rats, used as a model system amenable to monitoring, mapping and perturbation of neuronal circuits, live in complex social groups in the wild (Schweinfurth, 2020).…”

“…Integrative cross-species approaches are crucial in the understanding of the roots of social behavior and in the identification of the proximal and neural mechanisms of how we perceive, compute and react upon social information (Keysers and Gazzola, 2016; Schweinfurth, 2020). Norway rats, used as a model system amenable to monitoring, mapping and perturbation of neuronal circuits, live in complex social groups in the wild (Schweinfurth, 2020). This has motivated a wave of recent laboratory studies, that uncover the diversity and sophistication of rat’s social skills (Knapska et al 2006; Atsak et al 2011; Knapska et al 2010; Pereira et al 2012; Cruz et al 2020; Han et al 2019; Hernandez-Lallement et al 2020; Kashtelyan et al 2014; Daniel 1942; Conde-Moro et al 2019; Viana et al 2010; Bartal, Decety, and Mason 2011; Ben-Ami Bartal et al 2014; Márquez et al 2015; Kentrop et al 2020; Hillman and Bilkey 2012; Rutte and Taborsky 2007; 2008; Schuster and Perelberg 2004; Schneeberger, Dietz, and Taborsky 2012 see Schweinfurth 2020 for review), the neuronal basis of which are starting to be dissected (Hillman and Bilkey, 2012; Twining et al , 2017; Carrillo et al , 2019; Pereira, Farias and Moita, 2020).…”