Marine mammals

Question 1

What type of thermoregulation do marine mammals have?

Answer 1

They are homeothermic endotherms

Question 2

How do marine mammals reproduce?

Answer 2

They are viviparous and nurse young with milk

Question 3

What reproductive strategy do marine mammals follow?

Answer 3

K-selected (few offspring, long care, long life spans)

Question 4

What environments do marine mammals inhabit?

Answer 4

Partly or fully aquatic; distribution linked to ocean productivity

Question 5

What are the four main taxonomic groups of marine mammals?

Answer 5

• Cetaceans
• Pinnipeds
• Sirenians
• Fissipeds.

Question 6

Which group includes dolphins, porpoises, and whales?

Answer 6

Cetaceans (Order Artiodactyla)

Question 7

What distinguishes pinnipeds?

Answer 7

Aquatic mammals with flippers—includes seals, sea lions, walruses

Question 8

Which group includes herbivorous, fully aquatic mammals?

Answer 8

Sirenians (manatees and dugongs)

Question 9

Which fissipeds are marine?

Answer 9

Sea otters and polar bears

Question 10

What are the two suborders of cetaceans?

Answer 10

Mysticeti (baleen whales) and Odontoceti (toothed whales)

Question 11

How do baleen whales feed?

Answer 11

Filter feeding using baleen plates (e.g., lunge feeding, bubble netting)

Question 12

What is the role of baleen whale excrement in carbon cycling?

Answer 12

It fertilizes phytoplankton, enhancing ocean carbon uptake

Question 13

What are odontocetes adapted for?

Answer 13

Catching and tearing prey with peg-like teeth; many use echolocation

Question 14

Where do pinnipeds give birth?

Answer 14

On land or ice floes

Question 15

What makes sirenians unique among marine mammals?

Answer 15

They are fully aquatic and only herbivorous

Question 16

What is the main diet of polar bears?

Answer 16

ostly seals; they need ~2 kg of fat/day to maintain weight

Question 17

How do marine mammals conserve oxygen during dives?

Answer 17

High RBC count, collapsible lungs, bradycardia, and apneustic breathing

Question 18

What helps marine mammals maintain temperature in cold water?

Answer 18

Blubber, large body size (low SA:V), and counter-current heat exchange

Question 19

What adaptations reduce drag in marine mammals?

Answer 19

Streamlined bodies, internalized genitals/ears, reduced limb structures

Question 20

What motion do cetaceans and sirenians use for swimming?

Answer 20

Dorsoventral undulation

Question 21

Which cetaceans use echolocation?

Answer 21

All odontocetes

Question 22

How is sound produced and received in odontocetes?

Answer 22

Via phonic lips and the melon; sound is interpreted through returning echoes

Question 23

What tools are used for acoustic monitoring of marine mammals?

Answer 23

Hydrophones, sonobuoys, C-PODs, sound traps, animal-attached tags

Question 24

Where is most cetacean DNA data collected from?

Answer 24

Stranded animals

Question 25

What are some major threats to marine mammals?

Answer 25

Whaling, pollution, entanglement, habitat loss, and chemical exposure (e.g., PCBs)

Question 26

What can PCB exposure lead to in marine mammals?

Answer 26

Reproductive failure, disease vulnerability, shortened lifespans

Question 27

What trophic levels do marine mammals occupy?

Answer 27

From low (planktivores) to apex predators (e.g., orcas, polar bears)

Question 28

Why is niche partitioning important in marine mammals?

Answer 28

It prevents competition and enhances ecosystem resilience

Question 29

How might loss of a marine mammal species affect the ecosystem?

Answer 29

It can cause cascading effects due to limited functional redundancy

Question 30

How does climate change threaten marine mammals?

Answer 30

Through sea ice loss, rising temps, altered prey distribution, and ocean acidification