Adaptation to Cold in Arctic and Tropical Mammals and Birds in Relation to Body Temperature, Insulation, and Basal Metabolic Rate

Biodiversity, Distributions and Adaptations of Arctic Species in the Context of Environmental Change

“…Classical Arctic zoology typically focused on morphological and physiological adaptations to a life under extremely low winter temperatures (129,130). Physiological studies contribute to a mechanistic understanding of how Arctic animals cope with extreme environmental conditions (especially low temperatures), and what makes them different from their temperate counterparts.…”

“…Warmblooded animals that persist throughout the Arctic winter have thick coats of fur and feathers that often turn white (130). The body shapes of high Arctic mammals such as reindeer, collared lemmings, Arctic hares and Arctic foxes are rounder and their extremities shorter than their temperate counterparts (Allen's rule).…”

Thermoregulation and patterns of torpor in the spectacled dormouse,Graphiurus ocularis(A. Smith 1829) (Gliridae)

“…Cmin• the coefficient expressing the ease with which heat flows to or from an animal's body, and tl were calculated using the formula of SCHOLANDER et al (1950): C = BMR I T.-Tb, where C = Cmin(calci (Table 1).…”

Photoperiod and fur lengths in the arctic fox (Alopex lagopus L.)

“…Specifically, we discuss seasonal changes in the thermal quality of the fur and how growth of the fur may be timed to seasonal changes in environmental conditions. The amount of winter fur has been observed to be greater in arctic * mammals than in similar tropical species (Scholander, et al 1950). In arctic mammals up to the size of the Arctic fox (4 kg), a direct relationship exists between the length of winter fur and body size.…”

“…Tolerance of extreme cold by the Arctic fox is well-documented. Scholander, et al (1950) described the lower critical temperature of this species as "in excess of 40 0 C, " and Irving and Krog (1954) stated that the Arctic fox can withstand temperatures of -80 0 C for one hour with no decrease in rectal temperature. Irving (1964) speculated that in winter the Arctic fox can withstand -70 0 C by increasing the metabolic rate by only 37 percent above resting conditions.…”