Marine Mammal I Flashcards
describe marine mammals
- warm blooded
- air breathing
- fur or hair at some stage
- live young
- young suckle milk
what are examples of cetaceans?
- mysticetes
- whales
- porpoises
- dolphins
what is an example of sirenians?
sea cows
Sirenia
- manatees and dugongs
what’s an example of carnivora?
pinnipeds - sea otters
- seals
- walruses
- sea lions
what are archaeocetes?
primitive cetaceans
what is Pakicetus?
archaeocete from Pakistan
- first identified cetacean
describe Zeuglodon
- yolked tooth (double-rooted)
- originally called Basilosaurus-> originally thought to be a lizard
- small but well-developed hind limbs -> reduced as they became aquatic
- modern whales have very reduced hind limbs and pelvis
describe carnivora
- meat eating
- prominent canine teeth
- fur or blubber for warmth
- slow swimmers but agile
- dexterous limbs - hands for feeding
- live close to shore- breed on land
how do sea otters live?
- whole life in sea and seldom on land
what do sea otters eat?
- shellfish and crustaceans
- dive less than 30m but deep as 84m
how do sea otters eat?
- feed on surface
- carry stone under armpit to break open shells and urchins
- folds of skin used as shopping bags tucking clams and crabs away to eat later on
how do sea otters modify their habitat?
- selectively feed on molluscs and sea urchins
why is the sea otter population decreasing?
- hunted for fur
why is re-introductions difficult?
- not migratory species and stay in the same place
- territorial
how many babies do females have and what is their gestation?
- 1 pup per year
- 4-12 month gestation
-> delay implantation: common, when egg is fertilized there is delayed implantation so they can conserve energy until their own body has enough fat
how long do M and F live for?
- F: 15-20
- M: slightly shorter
what is the social life of sea otters?
- polygamous -> polygynous (more F than M)
- social
- live in rafts of same sex
- males are solitary and defend territories - fight for good territory so it’s attractive to F if you have good land
how many layers does the fur have?
- 2 layers - undercoat and long guard hairs
what is in between the layers?
air
- blow air bubbles into fur for insulation
- reduce amount of water touching the body so they can keep warm
why do they have to eat so much?
- live in cold water
- have to eat 25% of weight in food each day to keep warm
what kind of species are otters?
- keystone
-> preference of urchins modifies habitat - urchins graze kelps so they decreased
- otters remove urchins and grazing
- otters allow kelp to grow stabilizing water column nearshore (larval settlement)
what is the trophic cascade that has otters?
kelp
sea urchin
otter
killer whale
what happens when sea otter population is low?
killer whales eat lots of otters
otters eat less urchin
urchin population is high so graze on kelp lots
what happens when sea otter population is high?
sea urchin is low and kelp population is high
what are pinnipeds?
- seals
- sea lions
- walruses
which species are the most versatile?
pinnipeds
what kind of temps can pinnipeds tolerate?
extremes
where do pinnipeds live?
land and water
describe walruses
- 2 types: Northern Atlantic and pacific/arctic
- large
- tusks of ivory -> M have longer tusks which shows good mate or not -> sweep oceanfloor
- feed on benthic invertebrates (vibrissae= whiskers- sensitive)
- loss of hair - thick blubber insulates
what are true seals?
earless seals - Phocidae
how are Phocidae adapted to life in water?
- cannot move back limbs under body -> no standing
- good swimmers, use undulating motion of back flippers
- cold climate seal - fur and blubber
- ears are flat to head
- abundant in Arctic
what are sea/fur lions?
eared- Otariidae
- external ears
how are Otariidae adapted for life on land?
- move legs under body
- large flexible body
what are Otariidae social lives like?
- large social groups
- form harems to mate (5-15F : 1M)
- aggressive
how do Phocids feed?
- streamlined movement
- forage at great depths
- air forced from lungs
how do Otariids feeds?
- known for agility
- feed in upwelling areas close to breeding sites -> lots of productivity
what are Pinniped adaptations for swimming/hunting?
- 5-15 knots cruise speeds
- 25-30 knots for burst swimming
- fins and flippers for acceleration
- flippers are dexterous with claws to create breathing holes in sea ice
- neck vertebrae flexible
how do Pinniped move on land?
- true seals wriggle and leap out of water
- eared seals hind flippers rotate under body, good for walking
how do Pinniped regulate temps?
- large size allows for better control of heat loss and keep heat at core
- insulation blubber (walruses and elephant seals)
- fur: 2 layers
- arctic: fur and blubber
- pups use fur and adipose tissue (fat)
where do polar bears live?
sea ice
what are polar bears marine adaptations?
- head shape - streamlined, long neck to grab seals
- paws - long hair and grips
- lipivore - fat based diet
where do Dugongs live?
indo pacific
where do manatees live?
tropical atlantic
what kind of habitats for manatees and dugongs have?
- shallow bays
- eat sea grasses and invertebrates
- important for ecosystem diversity
what is reproduction like for manatees and dugongs?
- female bear 1 calf every 3-7 year
- live up to 70 years
what belong to the cetacea?
dolphins
whales
porpoises
describe cetacea
- mammals in sea
- warm blooded
- air breathing
- largest animals
- fast swimmers (muscular body, tail flukes with forelimbs used as stabilizers)
- dolphins (5-9 knots)
- rorquals (2-16 knots)
what is used to shed skin and reduce drag?
- skin secretes polymer - ethylene oxide droplets
what is used in perfume?
ambergris
- product of digestion
- in intestine and rectum of sperm whales
what are cetaceans common features?
- horizontal tail
- nearly hairless - blubber for warmth
- streamlined body for speed - less drag
- forelimbs modified into flippers
- specialized inner ear - ear canal in non-functional, lower jaw conducts sound to the inner ear which has lots of ganglia cells for better hearing
how do mysticetes sieve food?
fine plates of baleen
what is baleen?
protein formed like a comb
- fiber-like threads free on inner side that trap plankton
what do mysticetes filter?
shrimp and plankton
Which species sieve?
skim feeders
bulldozers
lunge feeders
how big is the bowhead whale mouth?
1/3 of body
how big are the bowhead whale baleen plates?
longest ever up to 4 m
what is the bowhead lifespan like?
longest lived mammals up to 200 years
what species are skim feeders?
right and bowhead whales
how do right whales eat?
skim the surface and high blubber content so float when dead
what kind of feeders are grey whales?
bulldozers
how do gray whales eat?
- skim plankton or bulldozing sediment to sieve worms and crustaceans
what side do gray whales prefer when bulldozing?
- right side bc often go blind in right eye from abrasion
how doe gray whales reproduce?
reproduce in south warm water and migrate north in summer to feed
what is the migration of gray whales like?
22,000km annual migration to summer polar feeding grounds
- winter mating and calving in Baja
how do whales travel?
- in pods for hunting and social
what is the number of whales in a pod dependent on?
abundance of food
what does Antarctic convergence have?
huge amounts of krill
what kinds of whales can be found in the same place?
right and sperm
what are lunge feeders?
- Rorquals = furrow whales
what doe Rorquals eat?
- lunges up through mass of plankton
what special feature do Rorquals have?
pleated expandable throat
what kind of species are Rorquals?
- minke
- fin
- humpback
- blue whales
how do Rorquals eat?
sieve plankton through sheets of baleen
- 3600 kg krill/day
- feed for 120 days
what is bubble net feeding?
- humpback whales feed cooperatively by generating bubble nets to force plankton into single place - work together
what are odontocetes?
toothed whales
what family do orcas and dolphins belong to?
delphindae
- killer whales
what kind of eaters are orcas?
social hunters that eat diverse prey
- generalists
- eat salmon, seals, otters and sharks
what are residents?
- little migration, eat salmon and fish
what are transients?
- migrate N and S BC coast
- eat seals, fish, otters, marine birds
- more generalists than residents
what are offshore?
live away from coast
- sharks
- less options
how can we distinguish residents, transients and offshores apart?
saddle patches
- differ in shape, size and opacity
what is Physeteridae?
sperm whales
what is a special feature of sperm whales?
spermaceti - product from head of sperm whales which echolocate
- 35% of body is the head - remarkable acoustic lens
- wax-like material
- acoustic lens or buoyancy
what is the purpose of echolocate?
send info out and direct auditory info
what results from irritation of squid beaks in intestine?
ambergris
what do sperm whales hunt?
giant squid in > 1000m depths
what species belong to monodontidae?
beluga and narwhal
where do beluga and narwhal live?
endemic to arctic
describe belugas
white
no dorsal fin (easy to swim under sea ice)
teeth to catch squid, fish and invertebrates
bulb on head for echolocation (34 calls)
travel in small group
summer in estuaries for moulting and calving (not enough fat for thermoregulation)
describe narwhals
- 2 canine teeth -> 1 grows into a tusk which is a status symbol and sensory organ
- feed on large fish
- lack dorsal fin
