LEC 13 - MARINE MAMMALS II (ADAPTATIONS)

Question 1

sperm whales can stay underwater for up to an hour. how?

Answer 1

0-10 min: descending to 1000m

10-30/40 min: hunting giant squid

then return

Question 2

what are the three main issues that u need to consider when deep sea diving?

Answer 2

1. nitrogen narcosis: nitrogen dissolved in blood visits the brain
2. embolism: blood vessels burst in lungs
3. the bends: under high pressure, nitrogen in air becomes liquid where it moves around in the body. when u surface too quickly, the gas turns to bubbles in tissue + joints – emotional damage.

Question 3

how bad is 100 atm anyways?

Answer 3

1 atm refers to atmospheric pressure, which we don’t notice bc we’re so accustomed to it

however when u imagine 100 atmospheres compressing down on u it feels kinda crazy

[100 atm is the equivalent of about 1469 lb/square inch pressing down on u! fun!]

Question 4

how are sperm whales adapted for deep diving? (avoiding nitrogen narcosis, embolisms, the bends) (5)

Answer 4

1. collapse lungs and store gas in trachea –> no gas exchange
2. efficient use of air
   where humans take in 20% air we breathe and use 4-5% of oxygen, sperm whales breathe in 90% of air and use 16% of oxygen
3. restrict circulation and store oxygen in blood + muscles due to crazy amounts of hemo- and myoglobin (prevents embolisms)
4. filter out nitrogen in blood going to brain (prevents nitrogen narcosis)
5. slow down heart rate, since blood is for the most part already where it needs to be

Question 5

why may odontecetes be affected by sonar tech but not mysticetes?

Answer 5

odontocetes use echolocation, so when it gets overloaded w sonar tech they freak tf out

mysticetes do not use echolocation as much, so they are not as likely to freak out

Question 6

in echolocation, what are low freq clicks, high freq clicks, and high freq whistles used for?

Answer 6

low freq clicks are used for seeing the landscape

high freq clicks are used for hunting (moving targets = high freq)

high freq whistles are used for communicating

Question 7

how does echolocation work in small toothed whales? (4 steps)

Answer 7

1. sound generated at the blowhole
2. sound rebounds off skull
3. melon focuses sound
4. sound exit

Question 8

how does echolocation work in sperm whales?

Answer 8

1. sound generated at the trachea, moving to the “monkey’s muzzle” to become a click
2. sound rebounds off skull (an air sac attached to skull, specifically)
3. sound focused in the junk (spermaceti containing organ)
4. sound exits

Question 9

what is so crazy about cetaceans having beeg brains? (3 things listed here)

Answer 9

• sociality (pods + whale aunties!)
• altruism
• can learn/be trained

Question 10

how do whales contribute to the productivity of the atlantic ocean?

Answer 10

shidding everywhere (esp helps w nitrogen and iron)