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+136ºF

+136ºF. -132ºF. Birds and mammals in cold environments The “thermoneutral zone” (TNZ). physiology…. morphology…. ecology…. behavior…. ambient temperature. lct. uct. low. high. The TNZ. Endothermic homeotherms and the thermal environment. increased blood flow sweating panting

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+136ºF

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  1. +136ºF

  2. -132ºF

  3. Birds and mammals in cold environments The “thermoneutral zone” (TNZ)

  4. physiology… morphology… ecology… behavior…

  5. ambient temperature lct uct low high The TNZ Endothermic homeotherms and the thermal environment increased blood flow sweating panting urination/salivation melon rinds heat exhaustion heat stroke BTR piloerection thigmotaxis increased MR (NST) shivering hypothermia

  6. solstice equinox

  7. Heterothermy

  8. Hibernation… cyclic prolonged protected regulated

  9. Hibernation…

  10. Torpor…

  11. Tb fall spring

  12. Energy Use during hibernation: Torpor: 16.6% Arousal: 19.0% Intertorpor Homeothermy: 51.6% Reentry into torpor: 12.8%

  13. brown fat body size white fat

  14. Water balance and heat load in mammals

  15. the Kangaroo Rat adaptive syndrome… Burrowing Nocturnal Granivorous

  16. Water balance and heat load in mammals Burrowing… …microhabitat “latrine” urine

  17. Water balance and heat load in mammals turbinate bones…

  18. Water balance and heat load in mammals Nocturnal

  19. Water balance and heat load in mammals Granivores Atkins diet? water? store seeds… store seeds…

  20. what about… Water balance and heat load in mammals burrowing nocturnal granivores - works for…

  21. Water balance and heat load in mammals Dromedary Camel can go without water… organisms are… Camels can drink 100 l of water in about 10 minutes…

  22. Water balance and heat load in mammals Camels: lose 25% of their body mass in water a 500 kg camel can lose 125 l of water… a human…?

  23. Water balance and heat load in mammals Hydrated camels evaporate 23 l per day… Tb 41 39 36 34 night Time day

  24. Water balance and heat load in mammals When under water stress… Tb 41 39 36 34 night Time day

  25. Water balance and heat load in mammals a hot pan… circadian temperature fluctuation… storage of heat… convective heat loss…

  26. Water balance and heat load in mammalsWhat does this accomplish? • reduced heat loading from env • reduced metabolic rate at night… • increased storage capacity… • reduced water loss… • storage of heat = saving of water • water is necessary for dissipation of heat…

  27. Water balance and heat load in mammals • How much water do camels save? • The SHC of camel flesh is 0.83 cal g-1oC-1 (or 0.83 kcal kg-1oC-1) • 500 kg camel: each degree of temperature increase = 415 kcal of stored heat (500 x 0.83 = 415) • How much water would be needed…?

  28. Water balance and heat load in mammals • What is the HV of water? • 540 cal g-1 (540 kcal l-1) • so for each 415 kcal… • 415 kcal /540 kcal l-1 = 0.768 l • 0.768 l per degree x 7 degrees = 5.38 l of water saved per day • What does this do for them?

  29. Water balance and heat load in mammals …camels evaporate 23 l per day… can lose 125 l of water… 125 l /23 l day-1 = 5.5 days 23 l - 5.28l = 17.62l 125/17.62 = 7.1 d…

  30. Water balance and heat load in mammals an extra day and a half…

  31. What is up with the hump? furry Other camel strategies…

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