|Murray M. Humphries||Research||People||Research Equipment||Pictures||Collaborators & Funding|
M.Sc. McGill University (2012)
Reporting Coordinator, Navus Environmental Inc
Correlates and consequences of heterothermy in mammals
Mammals are endotherms, capable of maintaining an elevated body temperature independent of their surroundings. Considerable variation exists, however, in the range of body temperatures expressed by a given species. For example, moose maintain a relatively stable body temperature, rarely varying by more than 1°C, while Arctic ground squirrels have been documented to drop their body temperature by close to 40°C. In my research, I examined factors, including body mass, latitude, climate, habitat, food habits, hoarding behaviour, and phylogeny, that may influence the degree of heterothermy expressed in a wide range of species.
In addition to this extensive inter-specific variation in body temperature, there is also considerable intra-specific variation, particularly in species that exhibit extreme heterothermy through a process known as torpor. Torpor allows animals to significantly reduce their energy requirements, through a reduction in body temperature and metabolic rate, during times when environmental conditions are harsh or food availability is low. The potential consequences associated with torpor bouts, however, remain unclear. Thus, secondly, I considered the potential behavioural costs of torpor, specifically focussing on exploration and spatial memory. To explore these costs I used captive eastern chipmunks as a model species in a series of behavioural tests as this species is known to show considerable individual variation in depth and duration of torpor expression. Overall, I am interested in gaining a better understanding of this widespread and complex survival strategy as, even with the current attention, numerous uncertainties remain.
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Created: January 2005
Last Updated: January 2014