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

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

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 Lasionycteris noctivagans Lasiurus cinerea

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

6. Heterothermy Homeothermy Eptesicus fuscus Thermal neutral zone

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

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

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

13. Desert Animals Potential evaporative water loss SMALL MAMMALS Larger relative surface area 1)Higher heat loads 2)Higher evaporative loss

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

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 Dilute Concentrated 1200 medulla

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

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

20. Marine mammals Temperature regulation

21. depth (m) duration (min) Humans skin diver 100 2 scuba 300 Deep Diving 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 DIVING feeding dives of sperm whale (Physeter macrocephalus )

23. Elephant Seal Diving AnimalsDivesDuration (min) Surface Interval (min) Mean MaxMean 21 Females 116,555 24 89 2 15 Males100,662 23 80 3 Depth (m) Mean Max 4931567 3651581 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. Phoca vitulina (common harbor seal) DEEP DIVING Diving Bradycardia - lower heart rate, blood diverted to essential organs From: Elsner (1988)

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

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

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