Download Gray whales

• marine mammals
•Ocean dwelling
•Depend on the ocean for its food
•marine mammals evolved to live in the ocean
50 mya
•after mammals originally evolved to live on
land
Evolution of Marine Mammals
• Land mammals evolved back into
marine animals 7 separate times
• A prehistoric deermouse is the link
between land animals and the whale
lineage
• New fossils suggest hippos are whales
closest living land relative
MAMMAL CHARACTERISTICS
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Breathe air with lungs
Have hair
Live birth
Mothers feed young milk
Endothermic- regulate body heat with
their metabolism
• 4 chambered heart
SOME ADAPTATIONS TO LIFE IN WATER
• Blubber and thick coats of hair to retain
heat
• Tetrapod limbs modified into swimming
appendages
– Swim by moving up and down
– Caudal tail is oriented horizontally
• Bodies modified for swimming: webbing,
hydrodynamic shapes
ADAPTATIONS cont….
• Collapsible lungs and rib cages for deep
diving
• Ability to slow heart rate and circulation to
extremities to increase dive time
• Record-1 1/2 hour long, 6000 ft deep dives
Ex.- Cuvier beaked whale
Other Marine Mammal
Characteristics
• Muscle cells carry more O2 then ours
• Higher tolerance to CO2
• Whales are conscious breathers and sleep
in pairs or while swimming in order to stay
alive
CLASSIFICATION
• Order- Cetacea
– Suborder Mysticeti
– Suborder Odontoceti
• Order Carnivora
– Suborder Pinnepedia
• Family Phocidae
• Family Otariidae
• Family Odobenidae
– Family Mustelidea
– Family Ursidae
Order Sirenia
Order Cetacea
• 80 different species, all completely
marine
• Intelligent social animals
• Two groups of whales
Mysteceti- baleen whales
– Filter feeders that eat plankton and
small fish
– Blue, finback, humpback, right and gray
whales
– To feed- open mouths and take in
enormous quantities of water and filter
out food
– Rorqual whales have pleated throats to
help collect more water
– Baleen- overlapping plates of protein
that strain out food
Baleen Feeding Methods
• Rorquals- take in huge gulps of water to
eat krill and small fish
• Right whales -swim through near surface
waters to skim and strain plankton
• Gray whales - bottom feeders that suck
up sediments to filter out small crustacean
and other invertebrates
• Humpback whales - blow bubble nets
to entrap prey
Rorqual Feeding Behavior
Right Whale Feeding Behavior
Gray Whale Feeding Behavior
Humpback Feeding Behavior
Order Odontoceti - toothed whales
• Peglike teeth to catch fish, seals,
penguins and squid
• Sperm, killer, pilot, beluga, dolphins
and porpoises
• Active hunters with specialized teeth
who swallow their prey whole
• Male narwhal tooth grows out of it’s
upper jaw
• Used to attract mates and sense its
environment
Whale Reproduction
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Fertilization and development are internal
Gestation lasts 11 to 18 months
Breeding once every three years
Great deal of parental care
– Newborns are brought to the surface for
their first breath
– Nursed for 6 to 10 months
– Milk is 50% fat so the calves can grow
quickly
Whale Adaptations and Behavior
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Breathing
Swimming
Other Movements
Migration
Keeping Warm
Communication
Breathing
• Breathing thru the blowhole (nostril)
• Thru whale evolution nostril moved from
the snout to the top of the head
• Air moves from nostril to the lungs
• Whales are conscious breathers
Swimming
• Tail flukes (hind flippers) propel them
forward
• Dorsal fin is used in directional control
• Pectoral fins are used in steering,
braking and balance
– Bone structure is similar to the bones in
hand
Other Movements
• Lobtailing- smashing tail down on the
surface of water (maybe displaying
aggression)
• Spyhopping- head is raised above water
surface for a period of time
• Breaching- leaps out of water and
crashes back down
Migration
• Whales travel 1000’s of km a year with
their pod (extended family)
• Navigate using geologic features, ocean
currents, water chemistry, magnetic field,
and sun
• Migrate between feeding and breeding
– Summer-feeding in rich Arctic waters
– Winter- Breed in warm, shallow and
secluded tropical waters
Keeping Warm
• Dive to cold and deep depths
– Sperm whale may dive to depths of
3000m
• Migrate to cold Arctic waters
• Posses thick layer of blubber under their
skin (layers of fat)
– Traps and prevents heat loss
– Can be 2 feet thick
Communication
• Large and well-developed brains
• Complex types of communication have
been documented
– Used in group hunting, finding mates,
sensing objects, locating prey
• Echolocation
• Humpback whales compose complex
songs which differ by individual and pod
Order Carnivora
• Suborder Pinnepedia
– Family Phocidae: True seals
• no external ears and crawl on land because
their front flippers are small
– Family Otariidae: Fur seals
• External ears and can walk on land
– Family Odobenidae: Walruses
• two long tusks, no external ears, but can
rotate their hind flippers and "walk" on land
Seals and Sea Lions and
Walruses
• Pad-like appendages and torpedo shaped
bodies
• Seals and sea lions are found in all oceans
while walruses are only polar
http://marinesciencetoday.com/wpcontent/uploads/2009/09/Walrus-US-Fishand-Wildlife.jpg
Pinniped Reproduction
• Return to land to mate and give birth
• Breeding season results in congregates of
1000’s
• Males usually compete for harems of
females with whom they mate
• Delayed development of embryos so birth
is exactly 12 months from mating
http://images.google.com/imgres?imgurl=http://www.polarcruises.com/antarctica/articles/photos/articles/ant_seals_mul_w008_3.jpg&imgrefurl=h
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Pinniped Adaptation
• Intelligent social animals who also use
communication
• Deep divers- elephant seal dives up to
1500m
• Thick layer of blubber insulation
• Thick fur
• Walruses have tusks for digging up
mollusks
Family Mustelidea Sea Otters
• Only recently adapted to aquatic life (3mya)
• Sleep, eat, mate and rear young in ocean
• Keystone species in kelp forests
– Feed on species that would otherwise destroy the
kelp (sea urchins and snails)
• Dive for shellfish, at surface use a rock to get
to their food
• Lack blubber but fur keeps them warm (1000
hairs per inch)
• Groom fur with special oils and trap air
bubbles in fur for increased insulation
http://www.uaa.alaska.edu/enri/aset/image
s/sea-otter.jpg
Threats to Sea Otters
• Oil spills- coats fur and prevents grooming
– Otters freeze because of the loss in insulation
• Past hunting for their prized fur decimated
otter populations almost to extinction
– Slowly recovering
• Predation-killer whales and sharks
http://owcnblog.files.wordpress.com/2009/02/oiledotter_rinse.jpg
Family Ursidae: Polar bears
• Most terrestrial marine mammal
• Lives on ice floes of the north polar region
• Thick fur, layer of blubber and hollow fur
hairs retain heat and insulate
• Not an excellent swimmer
• Hunt seals sunning on ice or coming up
thru ice holes to breathe
• Solitary animals
http://images.google.com/imgres?imgurl=http://3.bp.blogspot.com/_EqQZrgoXvqM/SZDFRcP3FFI/AAAAAAAACTo/hu4dD7Hf2bE/s400/Polar%2BBear%2Bwh
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Order Sirenia- Dugongs and Manatees
• live in warm or tropical waters
• feed on plants (herbivorous)
• Shy, social animals that communicate via
squeaks
• Winter upstream in warm coastal rivers
• the Steller sea cow, once inhabited Arctic
waters, but was hunted to extinction by
1768, within 27 years of its discovery
http://images.google.com/imgres?imgurl=http://www.nal.usda.gov/a
wic/newsletters/v6n2/graphics/manatee.jpg&imgrefurl=http://www.na
l.usda.gov/awic/newsletters/v6n2/6n2manat.htm&usg=__YaObfwjbE
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http://www.greenpeace.org/raw/image_fu
ll/international/photosvideos/photos/agentle-dugong-near-okinawa.jpg
Threats to Manatees
• Vulnerable to hunting, loss of habitat and
pollution
• Frequently injured or killed by powerboat
propellers
• Red tide toxins also cause manatee
deaths