Pelagic Marine Mammals


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Pelagic Marine Mammals

  1. 1. © 2011 Pearson Education, Inc.Marine Mammals Land-dwelling ancestors Warm-blooded Breathe air Hair/fur Bear live young Mammary glands for milk
  2. 2. © 2011 Pearson Education, Inc.Major Marine Mammal Groups
  3. 3. © 2011 Pearson Education, Inc.Order Carnivora Prominent canine teeth Sea otters Polar bears Pinnipeds Walruses Seals Sea lions Fur seals
  4. 4. Polar Bear, Pittsburgh Zoo and Aquarium
  5. 5. © 2011 Pearson Education, Inc.Carnivora
  6. 6. © 2011 Pearson Education, Inc.Seals vs. Sea Lions and Fur Seals Seals lack prominentear flaps Seals have smallerfront flippers Seals have fore flipperclaws Different hipstructures Different locomotionstrategies
  7. 7. © 2011 Pearson Education, Inc.Order Sirenia Herbivores Manatees Coastal areas of tropicalAtlantic Ocean Dugongs Coastal areas of Indianand western PacificOceans
  8. 8. © 2011 Pearson Education, Inc.Order Cetacea Whales, dolphins, porpoises Elongated skull Blowholes on top ofskull Few hairs Fluke – horizontaltail fin for verticalpropulsion
  9. 9. © 2011 Pearson Education, Inc.Order Cetacea
  10. 10. © 2011 Pearson Education, Inc.Order Cetacea Adaptations toincreaseswimming speed Streamlinedbodies Specialized skinstructure 80% water Stiff inner layer Narrow canalswith spongymaterialMr. Bantay at Discovery Cove, Florida (November 2011).
  11. 11. Discovery Cove, Florida. November 2011
  12. 12. © 2011 Pearson Education, Inc.Order Cetacea Adaptations for deep diving Use oxygen efficiently Able to absorb 90% ofoxygen inhaled Able to store largequantities of oxygen Able to reduce oxygenrequired for noncriticalorgans Muscles insensitive tobuildup of carbon dioxide Collapsible lungs
  13. 13. © 2011 Pearson Education, Inc.Order Cetacea Suborder Odontoceti(toothed) Dolphins, porpoises, killer whale, sperm whale Echolocation todetermine distance anddirection to objects Determine shape, sizeof objects
  14. 14. © 2011 Pearson Education, Inc.Dolphins vs. Porpoises Porpoises Smaller, morestout bodyshape Blunt snout Triangular,smaller dorsalfin Blunt or flatteeth Dolphins Larger, morestreamlinedshape Pointy teethlike killerwhales (orca)
  15. 15. © 2011 Pearson Education, Inc.Echolocation Good vision of marine mammals is limited by oceanconditions. Mammals emit clicks of different pitches. Low frequency – great distance High frequency – closer range Dolphins can detect schools of fish at more than 100 meters(330 feet).
  16. 16. © 2011 Pearson Education, Inc.Echolocation Toothed whales send sound through water. Sound is reflected, returned to the animal, andinterpreted. An evolved inner ear structure may help toothed whalespick up sounds. Increased marine noise pollution may affect cetaceanecholocation.
  17. 17. © 2011 Pearson Education, Inc.Echolocation
  18. 18. Sofar -Sound Frequency and Ranging channelUnderwater sound is used by many marine animals to sense theirenvironment, communicate, and find food. Underwater sound is also used by marinescientists to measure ocean depth, track objects in the water, and determine oceantemperature changes. Transmission of sound in the ocean is affected by watertemperature, pressure, and salinity. The normal variations in these properties with depthcombine to produce a minimum sound speed at a depth of about 1,000 meters. At thisdepth, sound travels relatively slowly compared to the speed of sound through water atgreater and lesser depths. The depth zone centered around this level of minimum soundspeed is called the Deep Sound Channel, and is also known as the SOFAR (soundfixing and ranging) Channel. Sound entering this layer tends to be trapped andchanneled along it, making this layer extremely efficient in transmitting sound forthousands of kilometers through the ocean.
  19. 19. © 2011 Pearson Education, Inc.Intelligence in Toothed Whales Large brainsrelative to bodysize Communicatewith each other Trainable
  20. 20. © 2011 Pearson Education, Inc.Order Cetacea SuborderMysticeti Baleen whales
  21. 21. Blue Whale, NYC Natural MuseumOrder Cetacea Blue whale, finback whale, humpback whale, graywhale, right whale
  22. 22. Right Whale
  23. 23. © 2011 Pearson Education, Inc.Use of Baleen Fibrous plates of baleen sieve prey items Vocalized sounds for various purposes
  24. 24. © 2011 Pearson Education, Inc.Gray Whale Migration 22,000 km (13,700miles) annualmigration from coastalArctic Ocean to BajaCalifornia and Mexico Feeding grounds inArctic (summer) Breeding and birthinggrounds in tropicaleastern Pacific (winter)
  25. 25. © 2011 Pearson Education, Inc.Whales as Endangered Species Fewer whales now thanbefore whaling International WhalingTreaty Hunting of gray whalebanned in 1938 Gray removed fromendangered list in 1993as populationrebounded
  26. 26. © 2011 Pearson Education, Inc.Gray Whale Friendly Behavior
  27. 27. © 2011 Pearson Education, Inc.Whaling International Whaling Commission (IWC) 1948 –established to manage whale hunting In 1986, 72 IWC nations banned whaling Three ways to legally hunt whales: Objection to IWC ban Scientific whaling Aboriginal subsistence whaling