The aim of our study was determine torpor use in the Siberian hamsters (Phodopus sungorus) tested in a wide gradient of ambient temperatures (Ta). Experiments were done on fed and food-deprived animals acclimated to winter-like and summer-like conditions. We found that neither fed nor unfed hamsters acclimated to winter-like or summer-like conditions selected low Ta's and entered torpor. Instead, food deprivation led to selection of higher Ta's and slight lowering of body temperature (Tb), especially during the rest-phase of the day. Our calculations show that this strategy may lead to higher energy savings than torpor would. We argue that torpor use is not a fixed strategy but is determined primarily by a thermal conditions available in the environment.
Although thermal cover receives attention from managers, variations in data regarding its use by ungulates hinders development of effective cover guidelines. We examined patterns of habitat selection and activity of radio-collared cow moose Alces alces Linnaeus, 1758 to determine if these 2 parameters were influenced by ambient thermal environment. Cow moose used sites with relatively denser forest canopies when conditions of heat stress existed in open areas. Use of open areas did not change with ambient temperature; some sites classed as open on forest cover maps, however, had willow canopies capable of providing thermal cover. An increase in the use of open sites from 11.00 to 24.00 hr corresponded to a simultaneous decrease in the likelihood of thermal stress in such areas; predator-avoidance was deemed unlikely to explain observed behaviour. Moose decreased activity and distance traveled between successive locations during hot periods. Summer thermal cover is a selected, manageable component of moose habitat in southern British Columbia.
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