• 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

• 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

• 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

ADAPTATIONS cont….

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 Order Sirenia

– Suborder Mysticeti– Suborder Odontoceti

• Order Carnivora– Suborder Pinnepedia

• Family Phocidae• Family Otariidae• Family Odobenidae

– Family Mustelidea– Family Ursidae

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• 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

• 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/wp-content/uploads/2009/09/Walrus-US-Fish-and-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=http://www.polarcruises.com/antarctica/articles/wildlife_4/seal-society_9.htm&usg=__QVXt6I-hqfQjbM4Bc6Nm85AnnmM=&h=225&w=300&sz=19&hl=en&start=16&sig2=HZimxmda6rzZMq8hs2R6xg&um=1&tbnid=poV2jEqdpws8nM:&tbnh=87&tbnw=116&prev=/images%3Fq%3Dbaby%2Bfurseals%2Bweaning%26hl%3Den%26safe%3Dactive%26um%3D1&ei=oR1CS8a7KZOI8QbIianQBg

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/images/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%2Bwhale%2Bdinner.jpg&imgrefurl=http://ecotime.blogspot.com/2009/02/february-9-hunting-season.html&usg=__tqEC12g5Spe7gnq-

p_Lmkv07BjQ=&h=286&w=400&sz=25&hl=en&start=31&sig2=WsVZsj1XNEnutxulr2aGvw&tbnid=NzY2cHjLDkB2zM:&tbnh=89&tbnw=124&prev=/images%3Fq%3Dpolar%2Bbear%2Bhunting%26gbv%3D2%26ndsp%3D18%26hl%3Den%26safe%3Dactive%26sa%3DN%26start%3D18&ei=MyZCS_2uCNTe8Aa-

otiVBw

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/awic/newsletters/v6n2/graphics/manatee.jpg&imgrefurl=http://www.nal.usda.gov/awic/newsletters/v6n2/6n2manat.htm&usg=__YaObfwjbEOvmk1ui1rZFm9q8HF8=&h=286&w=400&sz=12&hl=en&start=8&sig2=FE7_RUyz12rrlL5KUJPWzg&tbnid=nAIPTI99PR0gLM:&tbnh=89&tbnw=124&prev=/images%3Fq%3Dmanatees%26gbv%3D2%26hl%3Den%26safe%3Dactive&ei=2CdCS8OsBaOD8Qbhk-W3Ag

http://www.greenpeace.org/raw/image_full/international/photosvideos/photos/a-gentle-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