Winter Ecology – Mammalian Adaptations to Winter
Sheryn Olson, University of Colorado, Mountain Research Station
; Energy Balance: Purpose is maintenance of ________________: Metabolism and Thermal
Conductance must be adjusted as temperatures decrease. HOW? Using
M , , P and B
; Survival Mechanisms in winter (after Feldhammer, et. al, 2004, Table 8.1, p.117):
A : give two examples each (There are Nine!)
a. C (voles, squirrels, raccoons)
b. Construction, maintenance of ,
c. F :
3. Increase thermogenic capacity. HOW? by increasing HOW?
Increased & (weasels).
S (all mammals), NST – accomplished
with BAT - – an interscapular patch in bats, shrews.
; Countercurrent heat exchange (peripheral heterothermy) and rete mirabile:
- example: Beaver’s tail.
; Bergmann’s Rule:
- example: deer
; Allen’s Rule:
- example: foxes ears (arctic, desert kit)
; Gloger’s Rule:
- example: caribou
; Rapoport's Rule:
Regional heterothermy –
& Temporal heterothermy – Set Point –
Interscapular brown adipose tissue – produces called N .
Thermoneutral Zone –
Lower critical temperatures –
Upper critical temperatures –
Winter lethargy –
Thermal Conduction –
Expressed as formula:
Heimal threshold –
3. Review Questions
1. Define and explain the differences between: homeothermy, ectothermy, poikiothermy, and
2. Label the arrows in the diagram with appropriate radiation (thermal, reflected), conduction,
convection, and evaporation.
3. What factors do mammals use to maintain their body temperature around a set point?
b. A l ( , )
c. B examples:
d. M and m choices
4. Why is there debate about Bergmann’s, Gloger’s and Allen’s rules?
There are notable to the rules. Examples: