Marine Mammal Diversity Flashcards
What are 5 defining characteristics of marine mammals?
- ___-blooded
- ___-breathing
- ___ or __ at some stage in development
- __ young
- young ___ mothers ___
- warm
- air
- fur or hair
- live
- suckle mothers milk (mammary glands)
t/f
marine mammals evolved a long time ago (~200 mya)
false
marine mammals have come about quite recently (50mya)
What are the 3 orders of marine mammals? Live an example from each.
- Cetaceans (eg. sperm whales) ie all whales
- Sirenians (eg sirenia ie sea cows)
- Carnivora (eg sea otters)
The cetaceans are split into 2 groups:
1
2
- Mysticetes (baleen whales)
- Odontocetes (toothed whales)
what’s the zeuglodon?
ancestor to 2 groups of whales- prehistoric whale with small but well-developed hind limbs
modern whales have very reduced hind ___ and ___
limbs and pelvis
t/f
marine mammals don’t have huge diversity
true!
not many species within each order
- eg sirenians only have 6 species!
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
meat
canine
fur (blubber)
agile
dexterous - can use hands for feeding!
shore, breed on land
Sea otters, seals, polar bears, walruses, sea lions, and fur seals are part of which order of marine mammals?
carnivora
sea otters spend most of their time ____, and live mostly in the ___ (rarely go on __).
They’re very ____ of their home!
feeding
ocean (land)
territorial
What do sea otters eat? How do they get their food?
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
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
false!
they eat so many invertebrates that they can entirely change the ecosystem
sea otters are native to the ___ ___, but were hunted nearly to extinction at one point (hunted for their __)
north pacific
fur
Are sea otters a migratory species? How does that impact reintroducing the species?
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
Female sea otters have _ pup(s) per year, with a 4-12 month gestation. Why such a big range of gestation length?
1
Because they can delay gestation! Can determine which egg implants depending on feeding
Sea otters are ____, and they live in rafts of the same sex. What is the role of the males?
polygamous
males are solitary and defend territories
How do sea otters stay warm?
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
Sea otters are a keystone species. What does this mean for them and their enviro?
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
What happens when sea otters are overhunted?
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
Why is there conflict with some locals regarding the reintroduction of sea otters in areas?
Locals have become dependent on the abundant sea urchins for food
- if sea otters reintroduced, no more urchins for them
t/f
killer whales eat sea otters as their primary food
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
Pinnipeds are a subgroup of the _____, and includes sea lions, ____, and _____
carnivora
sea lions, seals, walruses
Pinnipeds are the most ____ of marine mammals:
- they can tolerate ____ extremes
- live in water and on land
- mostly found in the ___
versatile
temperature
arctic
How do walruses feed? What do they eat?
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
How do walruses stay warm?
Not fur! Loss of fur in walruses
They have blubber (up to 15cm thick!) to keep them warm
What are the main differences (2) between “true seals” and “fur seals”/ sea lions
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
___ seals (Phocidae) are ____
- they’re adapted for life in ___
- ___(can/cannot) move hind limbs under body
- live in __ climates
true
earless
water
cannot
cold- have fur and blubber & warm themselves on rocks
___ 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
fur seals and sea lions
ears
land
can
social groups
less cold
How do true seals (phocids) feed?
they forage at great depths- dive deep and air is forced from lungs
- very streamlined
- can turn over rocks etc to find food
How do fur seals/ sea lions (otariids) feed?
they feed in upwelling areas (shallower) close to breeding sites
- very agile!
What are some swimming and hunting adaptations that pinnipeds all have?
~10 knots cruise speed, can sprint up to 30 knots
- fins & flippers= rapid acceleration
- flippers are dexterous for scratching
- neck vertebrae are flexible
Pinnipeds have different methods of moving on land. Explain the difference between Otariids and Phocids.
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
How do pinnipeds regulate their temp?
- 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
Manatees and Dugongs are part of the order ___, and they can weigh up to ___kg.
Sirenia
400kg
What do sirenia eat? Where do they live?
Manatees/ dugongs live in shallow bays and eat sea grasses + invertebrates in the grasses (like worms)
How are manatees and dugongs important for ecosystem diversity?
They can die in ___ waters
- since they eat sea grass, they influence the stability provided by sea grass
warm (can die in waters below 20C)
Why are manatees and dugongs so hard to find today?
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)
What are the 2 groups of cetaceans (whales)?
- Mysticetes (baleen whales)
- Odontocetes (toothed whales)
Cetaceans are mammals that ___ to the sea; they are __-blooded and __ breathing
returned
warm-blooded
air-breathing
Cetaceans are fast swimmers; they have a ___ body and __ flukes with forelimbs are used as ___
muscular
tail
stabilizers
How do Cetaceans reduce drag?
their skin secretes a polymer (ethylene oxide) that causes their skin to shed
- this removed barnacles/ moss etc on the skin and reduces drag
Sperm whales produce ambergris, what is it?
a product of digestion- not sure whether they vomit or poop it out
- used in perfume- very expensive
