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Hibernation in arctic mammals. Kelly Drew Brian Barnes Institute of Arctic Biology
arctic ground squirrel (Urocitellus parryii)
Brian Barnes Institute of Arctic Biology arctic ground squirrel ( - - PowerPoint PPT Presentation
Brian Barnes Institute of Arctic Biology arctic ground squirrel ( - - PowerPoint PPT Presentation
Hibernation in arctic mammals. Kelly Drew Brian Barnes Institute of Arctic Biology arctic ground squirrel ( Urocitellus parryii ) Arctic ground squirrels supercool their body fluids during hibernation. Two year record of core body temperature
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Arctic ground squirrels supercool their body fluids during hibernation.
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314 female arctic ground squirrel
8/1/98 12/1/98 4/1/99 8/1/99 12/1/99 4/1/00
body temperature (°C)
- 5
5 10 15 20 25 30 35 40 45
Fall Winter Spring Summer Fall Winter Spring
Two year record of core body temperature of a free- living arctic ground squirrel in northern Alaska.
- 32
- 95
- 104
(oF)
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Hibernating ground squirrels suppress metabolism first, then body temperature falls.
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08/01/98 10/01/98 12/01/98 02/01/99 04/01/99 06/01/99
body temperature (oC)
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5 10 15 20 25 30 35 40 45
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arousal and re-entry at ambient temperature -5oC
5 10 15 20 25 30 35 40 45
metablic rate (ml O2/gm/hr)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
body temperature (oC)
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5 10 15 20 25 30 35 40
activity
250 500 750 1000
Tb VO2 act
.
hours BMR
Karpovich S, Toien O, CL Buck and Barnes BM. 2009. Energetics of arousal episodes under arctic conditions in arctic ground squirrels. J Comp Physiol 179 691-700 basal metabolism
metabolic rate
body temperature activity
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arousal and re-entry at ambient temperature -5oC
5 10 15 20
metablic rate (ml O2/gm/hr)
0.0 0.2 0.4 0.6 0.8
body temperature (oC)
- 5
5 10 15 20 25 30 35 40
activity
250 500 750 1000
Tb VO2 act
.
hours
body temperature metabolic rate activity
BMR
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Stroke and heart attack are a problem
- f:
(Blood) supply = (metabolic) demand.
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Stroke and heart attack are a problem
- f:
(metabolic) demand. (Blood) supply ≠
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Stroke and heart attack are a problem
- f:
(Blood) supply (metabolic) demand. =
Create stasis, time for transport to advanced medical care.
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arousal and re-entry at ambient temperature -5oC
5 10 15 20
metablic rate (ml O2/gm/hr)
0.0 0.2 0.4 0.6 0.8
body temperature (oC)
- 5
5 10 15 20 25 30 35 40
activity
250 500 750 1000
Tb VO2 act
.
hours
body temperature metabolic rate activity
BMR
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American black bear Arctic ground squirrel
Comparison of the mammalian hibernation phenotype in human-sized and small hibernators.
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Photo by J. Hechtel
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Sep Oct Nov Dec Jan Feb Mar Apr May body temperature (oC)
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5 10 15 20 25 30 35 40 45
black bear arctic ground squirrel
contrast of body temperatures during hibernation in small and large mammals Hibernating black bears are human- sized, do not need to eat, drink, defecate or urinate for 7 months, do not lose muscle or bone mass, and can be wakened at anytime.
Tøien et al. 2011 Science