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Temperature regulation and metabolism

Temperature regulation and metabolism. Heterothermy. Daily Seasonal. Myotis Tenrec Bradypus Macaca. Homeothermy. Costs of Endothermy metabolic response to temperature extremes. low high.

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Temperature regulation and metabolism

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  1. Temperature regulation and metabolism Heterothermy Daily Seasonal Myotis Tenrec Bradypus Macaca Homeothermy

  2. Costs of Endothermy metabolic response to temperature extremes low high Ambient temperature

  3. Metabolic rate and body size SMALL MAMMALS Larger relative surface area Higher rates of heat exchange

  4. Coping with seasonal environments -- Migration Lasiurus cinerea Lasiurus cinerea Lasionycteris noctivagans

  5. COPING WITH COLD Temperature profile Snow surface Subnivean zone -30° -20° -10° 0° Mouse runways gopher “eskers”

  6. Thermal neutral zone Heterothermy Eptesicus fuscus Homeothermy Heterothermy

  7. Heterothermy -- Daily torpor Chaetodipus californicus 10 h torpor bout

  8. Heterothermy -- Daily torpor 85% energy savings

  9. Seasonal heterothermy Hibernation (winter dormancy) Spermophilus parryii arousal bout

  10. Active 4 months (spring growing season) Dormant 8 months (hottest AND coldest months) Seasonal heterothermy Hibernation + Aestivation (winter + summer dormancy) Spermophilus mollis

  11. Soil temperature profile -- Great Basin Temperature (°C) -5 10 15

  12. COPING WITH HEAT Behavioral & Physiological tolerance August Ammospermophilus leucurus Year-round daytime activity BUT Seasonal shift in behavior January Summer heat avoidance Daily activity profile (mid-summer) Surface activity bouts (and resting in shade) underground

  13. Desert Animals Potential evaporative water loss • SMALL MAMMALS • Larger relative surface area • Higher heat loads • Higher evaporative loss

  14. Burrow microclimate Sundevall’s Jird (Meriones crassus) Negev Desert, Israel Mid-summer profiles Daytime (underground) Temperature Burrow Surface Relative Humidity Burrow Surface

  15. Water conservation in desert rodents Merriam’s Kangaroo rat (Dipodomys merriami) Southwestern US

  16. Water conservation in desert rodents Ord’s kangaroo rat (Dipodomys ordii) Western US

  17. Kidney structure and water conservation medulla 1200 Dilute Concentrated

  18. Desert adaptations in large mammals (Camelidae) Guanaco (Lama guanaco) Bactrian Camel (Camelus bactrianus) Dromedary (Camelus Dromidarius)

  19. Countercurrent heat exchange Keeping the brain cool Keeping extremities warm

  20. Marine mammals Temperature regulation

  21. Deep Diving depth (m) duration (min) Humans skin diver 100 2 scuba 300 Human technology attack submarine test depth 400 “crush” depth 600 research submarine Alvin 4,500 bathyscaphe Trieste 10,912 Otariidae fur seal 200 8 sea lion 250 10 Phocidae Harbor seal 200 10 Weddell seal 600 73 Elephant seal 1,600 90 Whales Fin whale 500 20 Pilot wale 610 Beluga 650 20 Killer whale 1,000+ Sperm whale (feeding) 500-1000 (record) 3,200 80 (maximum) ?

  22. DEEP DIVINGfeeding dives of sperm whale (Physeter macrocephalus)

  23. DEEP DIVING -- feeding dives of elephant seal (Mirounga angustirostris)

  24. DIVING PROBLEMS Problem 1 -- Oxygen supply Physiological adaptations: Increased blood volume & hematocrit more hemoglobin and myoglobin selective shunting of blood, lower heart rate lower metabolic expenditure higher tolerance of CO2 & lactic acid

  25. DEEP DIVING Diving Bradycardia - lower heart rate, blood diverted to essential organs Phoca vitulina (common harbor seal) From: Elsner (1988)

  26. DEEP DIVING Reduced energy expenditure during dive (Mirounga angustirostris) Passive gliding descent Active stroking

  27. DIVING PROBLEMS Problem 2 – Water pressure Problem 3 -- Nitrogen Decompression sickness the “bends” Nitrogen narcosis

  28. Sperm whale (Physeter macrocephalus) Spermaceti organ Possible functions: Hydrostatic Echolocation Weapon (ram)

  29. DIVING PROBLEMS Problem 4 -- Navigation Foraging at depths where there is little or no ambient light Toothed whales sophisticated underwater sonar Seals -- Don’t have echolocation Acute “passive” hearing High visual acuity Sensitive tactile vibrissae

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