1. 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

2. 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

4. MAMMAL CHARACTERISTICS
Breathe air with lungs
Have hair
Live birth
Mothers feed young milk
Endothermic- regulate body heat with their metabolism
4 chambered heart

5. 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

6. 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

7. 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

8. CLASSIFICATION Order- Cetacea Order Sirenia Order Carnivora
Suborder Mysticeti
Suborder Odontoceti
Order Carnivora
Suborder Pinnepedia
Family Phocidae
Family Otariidae
Family Odobenidae
Family Mustelidea
Family Ursidae

9. Order Cetacea 80 different species, all completely marine
Intelligent social animals
Two groups of whales

10. 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

12. 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

13. Rorqual Feeding Behavior

14. Right Whale Feeding Behavior

15. Gray Whale Feeding Behavior

16. Humpback Feeding Behavior

17. 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

19. 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

20. Whale Adaptations and Behavior
Breathing
Swimming
Other Movements
Migration
Keeping Warm
Communication

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. Order Carnivora Family Otariidae: Fur seals 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

28. 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

29. 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

30. http://images. google. com/imgres. imgurl=http://www. polarcruises

31. 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

32. 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

34. 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

37. 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

38. http://images. google. com/imgres. imgurl=http://3. bp. blogspot

39. 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

40. http://images. google. com/imgres. imgurl=http://www. nal. usda

41. 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