Marine Mammal Diversity

Question 1

What are 5 defining characteristics of marine mammals?
- ___-blooded
- ___-breathing
- ___ or __ at some stage in development
- __ young
- young ___ mothers ___

Answer 1

• warm
• air
• fur or hair
• live
• suckle mothers milk (mammary glands)

Question 2

t/f
marine mammals evolved a long time ago (~200 mya)

Answer 2

false

marine mammals have come about quite recently (50mya)

Question 3

What are the 3 orders of marine mammals? Live an example from each.

Answer 3

1. Cetaceans (eg. sperm whales) ie all whales
2. Sirenians (eg sirenia ie sea cows)
3. Carnivora (eg sea otters)

Question 4

The cetaceans are split into 2 groups:
1
2

Answer 4

1. Mysticetes (baleen whales)
2. Odontocetes (toothed whales)

Question 5

what’s the zeuglodon?

Answer 5

ancestor to 2 groups of whales- prehistoric whale with small but well-developed hind limbs

Question 6

modern whales have very reduced hind ___ and ___

Answer 6

limbs and pelvis

Question 7

t/f
marine mammals don’t have huge diversity

Answer 7

true!

not many species within each order
- eg sirenians only have 6 species!

Question 8

Characteristics of Carnivora:
- __-eating
- prominent __ teeth
- still have __ (use that and/or __ for warmth)
- slower swimmers (don’t cover great distances) but ___
- ____ limbs
- love close to ___ and ___ on land

Answer 8

meat
canine
fur (blubber)
agile
dexterous - can use hands for feeding!
shore, breed on land

Question 9

Sea otters, seals, polar bears, walruses, sea lions, and fur seals are part of which order of marine mammals?

Answer 9

carnivora

Question 10

sea otters spend most of their time ____, and live mostly in the ___ (rarely go on __).

They’re very ____ of their home!

Answer 10

feeding
ocean (land)
territorial

Question 11

What do sea otters eat? How do they get their food?

Answer 11

feed on shellfish and crustaceans

• dive ~30m (up tp 84m!) through kelp forests etc and collect their food (then tuck it into skin folds to bring to the surface)
• can use their hands to turn over stones etc
• carry a rock in their armpit to break open shells etc

Question 12

t/f
sea otters eat a lot of molluscs and sea urchins, but not to the extent that it starts to change the ecosystem structure

Answer 12

false!

they eat so many invertebrates that they can entirely change the ecosystem

Question 13

sea otters are native to the ___ ___, but were hunted nearly to extinction at one point (hunted for their __)

Answer 13

north pacific

fur

Question 14

Are sea otters a migratory species? How does that impact reintroducing the species?

Answer 14

no, they stay in one place and are very territorial

• re-introductions are difficult b/c they’re so territorial and don’t move around

Question 15

Female sea otters have _ pup(s) per year, with a 4-12 month gestation. Why such a big range of gestation length?

Answer 15

1
Because they can delay gestation! Can determine which egg implants depending on feeding

Question 16

Sea otters are ____, and they live in rafts of the same sex. What is the role of the males?

Answer 16

polygamous

males are solitary and defend territories

Question 17

How do sea otters stay warm?

Answer 17

Extremely thick fur (2 layers- undercoat and guard hairs)
- between the layers there’s air, and they blow bubbles in for insulation!

They also eat a lot! eat 25% of their weight in food each day to stay warm

Question 18

Sea otters are a keystone species. What does this mean for them and their enviro?

Answer 18

Keystone= remove the sea otters = entirely changes their habitat and ecosystem

• preference for urchins modifies the habitat
• urchins eat kelp forests
• large numbers of sea otters keep urchin levels down and kelp stays abundant
• otters allow kelp to grow, stabilizing the water column close to shore, where larvae etc settles

Question 19

What happens when sea otters are overhunted?

Answer 19

urchin populations explode, and they destroy the kelp forests (that’s their primary food)
- no kelp forests= water column doesn’t stop moving= larvae can’t settle

Question 20

Why is there conflict with some locals regarding the reintroduction of sea otters in areas?

Answer 20

Locals have become dependent on the abundant sea urchins for food
- if sea otters reintroduced, no more urchins for them

Question 21

t/f
killer whales eat sea otters as their primary food

Answer 21

false

they do eat them sometimes, and can impact their populations.
Not ideal food b/c so much fur
Means the killer whales had nothing else to eat

Question 22

Pinnipeds are a subgroup of the _____, and includes sea lions, ____, and _____

Answer 22

carnivora

sea lions, seals, walruses

Question 23

Pinnipeds are the most ____ of marine mammals:
- they can tolerate ____ extremes
- live in water and on land
- mostly found in the ___

Answer 23

versatile

temperature
arctic

Question 24

How do walruses feed? What do they eat?

Answer 24

They use vibrissae (whiskers)
- they’re sensory- feel ground around them to find clams to eat

• use ivory tusks to dig for food sometimes, but don’t use for eating

They eat benthic invertebrates

Question 25

How do walruses stay warm?

Answer 25

Not fur! Loss of fur in walruses They have blubber (up to 15cm thick!) to keep them warm

Question 26

What are the main differences (2) between "true seals" and "fur seals"/ sea lions

Answer 26

true seals (Phocidae) are earless - adapated for life in water fur seals and sea lions (Otariidae) have ears and flaps over ears - adapted for life on land

Question 27

___ seals (Phocidae) are ____ - they're adapted for life in ___ - ___(can/cannot) move hind limbs under body - live in __ climates

Answer 27

true earless water cannot cold- have fur and blubber & warm themselves on rocks

Question 28

___ seals (otariidae) have ___ - they're adapted for life on __ - ___(can/cannot) move legs under body and move quickly - live in large ___ ___ and can be aggressive - more common is less ___ climates

Answer 28

fur seals and sea lions ears land can social groups less cold

Question 29

How do true seals (phocids) feed?

Answer 29

they forage at great depths- dive deep and air is forced from lungs - very streamlined - can turn over rocks etc to find food

Question 30

How do fur seals/ sea lions (otariids) feed?

Answer 30

they feed in upwelling areas (shallower) close to breeding sites - very agile!

Question 31

What are some swimming and hunting adaptations that pinnipeds all have?

Answer 31

~10 knots cruise speed, can sprint up to 30 knots - fins & flippers= rapid acceleration - flippers are dexterous for scratching - neck vertebrae are flexible

Question 32

Pinnipeds have different methods of moving on land. Explain the difference between Otariids and Phocids.

Answer 32

Otariids (fur seals) have hind flippers that can rotate under the body and be used to walk Phocids (true seals) can wiggle on land and leap out of the water, but can't walk on land

Question 33

How do pinnipeds regulate their temp?

Answer 33

- large size= better control of heat loss - in walruses and elephant seals, they have a lot of blubber to insulate - seals and otters have 2 layers of fur (inner layer is filled with air) - pups use fur and a layer of adipose tissue (fat) that turns into blubber later

Question 34

Manatees and Dugongs are part of the order ___, and they can weigh up to ___kg.

Answer 34

Sirenia 400kg

Question 35

What do sirenia eat? Where do they live?

Answer 35

Manatees/ dugongs live in shallow bays and eat sea grasses + invertebrates in the grasses (like worms)

Question 36

How are manatees and dugongs important for ecosystem diversity? They can die in ___ waters

Answer 36

- since they eat sea grass, they influence the stability provided by sea grass warm (can die in waters below 20C)

Question 37

Why are manatees and dugongs so hard to find today?

Answer 37

They're easy to hunt b/c they're slow & live in shallow waters= been overhunted - very low fecundity (live 70yrs, and females only produce 1 calf every 3-7yrs)

Question 38

What are the 2 groups of cetaceans (whales)?

Answer 38

1. Mysticetes (baleen whales) 2. Odontocetes (toothed whales)

Question 39

Cetaceans are mammals that ___ to the sea; they are __-blooded and __ breathing

Answer 39

returned warm-blooded air-breathing

Question 40

Cetaceans are fast swimmers; they have a ___ body and __ flukes with forelimbs are used as ___

Answer 40

muscular tail stabilizers

Question 41

How do Cetaceans reduce drag?

Answer 41

their skin secretes a polymer (ethylene oxide) that causes their skin to shed - this removed barnacles/ moss etc on the skin and reduces drag

Question 42

Sperm whales produce ambergris, what is it?

Answer 42

a product of digestion- not sure whether they vomit or poop it out - used in perfume- very expensive