Study of the social hierarchy and territoriality of Calomys callosus Rengger, 1830 (Rodentia: Cricetidae)

Abstract

The genus Calomys comprises a lot of species distributed throughout South America. The species C. callosus Rengger, 1830 occur in Brazil, been often used in laboratory experiments. This work involved a study of aggressive behavior and dominance, which are aspects related to hierarchy and territoriality, among C. callosus males kept in a laboratory. The establishment of a hierarchy was observed, with the dominant animals controlling the space, food and water, while the remaining animals were confined to a restricted space. The intensity of aggression and variations in the number of attacks declined over time as a result of the formation of the hierarchy. No wounds were observed, probably due to the ritualistic nature of the attacks.Keywords: social hierarchy, territoriality, Calomys callosus. Estudo da hierarquia social e territorialidade em Calomys callosusResumo O genêro Calomys inclui várias espécies encontradas na América do Sul. A espécie C. callosus Rengger, 1830 ocorre no Brasil, sendo freqüentemente utilizada em experimentos de laboratório. Neste trabalho foram estudados, em machos mantidos em laboratório, o comportamento agressivo e a dominância, aspectos relacionados à hierarquia e territorialidade. Foi observado o estabelecimento de hierarquia, com os animais dominantes controlando o espaço, o alimento e a água, ficando os demais confinados em um espaço restrito. A intensidade das agressões e as variações no número de ataques diminuiram com o tempo, uma conseqüência da formação de hierarquia. Não foram observados ferimentos, devido provavelmente à ritualização dos ataques.Palavras-chave: hierarquia social, territorialidade, Calomys callosus.

Manifestations of domination: Assessments of social dominance in rodents

“…When these partitions are removed by the experimenter, subjects are able to interact directly, allowing for the observation of agonistic behaviors. 32,[59][60][61][62][63][64][65][66][67][68] This assay has been used to identify dominance hierarchies in male Long Evans rats, 32,66 male BALB/cJ mice, 59 male NMRI mice, 63 male CD1 mice, 64 male large vesper mice (Calomys callosus), 65 male and female hamsters, [60][61][62]68 and male gerbils. 67 As in single-housed designs, these experiments are particularly useful when investigating social rank in highly aggressive species and strains, that if housed in standard F I G U R E 2 Schematics of experimental setup for agonistic behavioral analyses.…”

“…Thus, agonistic behaviors have also been analyzed in rodents that are housed in the same cage, but separated by barriers or partitions to prevent constant, direct physical contact. When these partitions are removed by the experimenter, subjects are able to interact directly, allowing for the observation of agonistic behaviors 32,59‐68 . This assay has been used to identify dominance hierarchies in male Long Evans rats, 32,66 male BALB/cJ mice, 59 male NMRI mice, 63 male CD1 mice, 64 male large vesper mice ( Calomys callosus ), 65 male and female hamsters, 60‐62,68 and male gerbils 67 .…”