title: Thermoregulation by an Australian murine rodent, the ash-grey mouse (Pseudomys albocinereus).
abstract: We examine here the thermal physiology of the ash-grey mouse, as there is a paucity of data to explain how Australian rodents meet thermoregulatory demands. Most ash-grey mice remained normothermic over a range of ambient temperatures (10 °C to 30 °C), although they became hyperthermic at high ambient temperatures. One individual entered torpor at ambient temperatures of 20 °C and 25 °C, with minimal body temperatures of 24.5 °C and 28.4 °C respectively, before spontaneously arousing. This is the first evidence of torpor use by an Australian murine rodent. Our data suggest that although ash-grey mice have the physiological ability to use torpor, it is used rarely, presumably due to other behavioural and physiological adaptations. Their higher-than-expected basal metabolic rate (1.56±0.25 mL O(2)g(-1) h(-1)) indicates that ash-grey mice do not have a frugal approach to energy expenditure. Other standard physiological variables were typical of a generalised rodent. A readily-available omnivorous diet, nocturnal activity, semi-fossorial habit and social behaviour presumably allow a high energy lifestyle. A reluctance to use torpor, despite an apparent physiological ability to do so, supports the idea that the use of torpor reflects a net balance between the costs and benefits of a heterothermic thermoregulatory strategy.
authors.affiliation: Department of Environment and Agriculture, Curtin University, PO Box U1987 Perth, Western Australia 6845, Australia. Justine.barker@postgrad.curtin.edu.au
authors.forename: Justine M
authors.initials: JM
authors.lastname: Barker
authors.forename: Christine E
authors.initials: CE
authors.lastname: Cooper
authors.forename: Philip C
authors.initials: PC
authors.lastname: Withers
authors.forename: Ariovaldo P
authors.initials: AP
authors.lastname: Cruz-Neto
mesh_terms: D000818:Animals; D001481:Basal Metabolism; D001833:Body Temperature Regulation; D005260:Female; D008297:Male; D051189:Murinae / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption; D010802:Phylogeny; D014904:Western Australia