Behavioural impacts of torpor expression: A transient effect in captive eastern chipmunks (Tamias striatus)

Species use torpor, an extreme form of heterothermy, to survive periods of limited resource supply. Studies of hibernating animals have shown that torpor causes major structural and physiological changes in the brain, many of which are reversed during periodic arousals. This suggests that behaviour may change during and following the hibernation period. Here we investigate individual performance in behavioural tests prior to and during hibernation by captive eastern chipmunks (Tamias striatus). Results indicate an association between deep torpor expression and atypical habituation patterns tested directly following torpor arousals. However, no association was found between torpor expression and spatial maze performance tested more than 24 h post-arousal. Therefore, any behavioural impairment induced by torpor appears to be highly transient. The detected association between torpor and behaviour may be driven by previously confirmed effects of torpor on brain structure and function, though other potential covariates, such as the activation and deactivation of the stress axis, warrant consideration. Thus, our results are consistent with transient behavioural impairments following torpor arousals, but the causes and longer-term consequences of these transient impairments remain unclear.

► We examine the behavioural effects of various degrees of torpor expression. ► Atypical habituation was noted in the open field 24 h following arousal. ► Maze performance tested later in arousal was not affected by torpor expression. ► Torpor imposes immediate functional costs on hibernators. ► Longer-term effects of torpor, and impacts on fitness, may be inconsequential.