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Great White Shark
https://www.youtube.com/watch?v=zZVbSYRC9P0
https://www.youtube.com/watch?v=Pk-G8g3wXOg
Marine Mammals
Cetaceans Pinnipeds
Sirenians Polar bear
Sea otter
What’s the big deal about being an aquatic mammal?
Problem and Solutions
Problem:
•Heat conductivity of water 25x that of air
Solutions?
Solutions
Insulation
Marine mammals - two forms of insulation
•Fur •Blubber
INSULATION THICKNESS (mm)
10 30 50 70 90 1100
0.5
1.0
1.5IN
SU
LA
TIO
N (
W-1M
2oC
)Still Air Dry Fur
Wood
Adipose
MuscleWater
Copper
Sea otter hair, Wet
Harbor porpoise blubber
Spotted dolphin blubber
INSULATION THICKNESS (mm)
10 30 50 70 90 1100
0.5
1.0
1.5IN
SU
LA
TIO
N (
W-1M
2oC
Still Air Dry Fur
Wood
Adipose
MuscleWater
Copper
Polar bear hair, Dry
Polar bear hair, Wet
Thermal Windows
•Feet
•Flippers•Dorsal fin
•Pectoral flippers
•Tailflukes
Rommel et al., ‘98
Countercurrent exchanger
Conclusions
Marine mammal solutions
•Insulation - fur and blubber
•Vasculature
Thermal Problem for Male Reproductive Systems
Problem:
• Sperm production requires lower temp
Terrestrial mammal solution
• Scrotum or cremaster sacs
Rommel et al., ‘98
The Cetacean Solution
Rommel et al., ‘92
Rommel et al., ‘98
12
34
5
Distance from Anus (cm)
Tem
pera
ture
(o C
)
37
36
35
IT WORKS!
Conclusions
Marine mammal solutions
•Decreased surface area
•Insulation - fur and blubber
•Vasculature
Structure without function is a corpse; function sans structure is a ghost - Vogel and Wainwright, ‘69
