Marine Mammals

Question 1

Surface-to-Volume ratio… What occurs with increase in:

Volume?

Surface?

Answer 1

Volume = Heat production

Surface = Heat dissipation

Question 2

How do marine mammals increase volume?

Answer 2

Blubber: Lipid content influences thermal conductance

Hair: Increase density (to maintain volume when wet); Trap air, remain waterproof

Question 3

What is brown fat?

Answer 3

Contains loads of mitochondria

• Metabolised for thermogenesis: Useful for seal pups born without insulative blubber - prevalent in mammalian new-borns

Used in CCHE too

Question 4

What is Allen’s Rule?

Answer 4

The principle holding that in a warm-blooded animal species having distinct geographic populations, the limbs, ears and other appendages of the animals living in cold climates, tend to be shorter than animals of the same species living in warm climates.

Question 5

What is Bergmann’s rule?

Answer 5

Body size is large in cold climates and small in warm climates

Question 6

What does CCHE stand for?

Answer 6

Counter-Current Heat Exchanges

Question 7

What are the 3 types of divers?

Answer 7

Shallow divers (e.g. sea otters)

Intermediate divers (e.g. bottlenose dolphin, Sea lion)

Deep divers (e.g. Weddell seal)

Question 8

What is the mammalian dive response?

Answer 8

• Breathing cessation
• Bradycardia
• Vasoconstriction
• Reduced aerobic metabolism
• O2 depletion
• Increase in CO2
• Lactic acid accumulation

Question 9

What is DLT?

Answer 9

Diving Lactate Threshold

When anaerobic respiration starts

Question 10

What is cADL?

Answer 10

Calculated ADL

Time it takes for all the usable O2 stores to be consumed

cADL is never reached because anaerobic respiration kicks in progressively