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Marine Mammals: Part 3

Marine Mammals: Part 3. Marine Vertebrates: Lecture 9. Cetacea Origins Archaeocetes (~50 mya). Pakicetus Long, slender jaws Simple teeth Dorsal blowhole Robust pelvis and hindlimbs. Cetacea Origins Archaeocetes (~50 mya). Basilosaurus More obviously aquatic Reduced hindlimbs.

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Marine Mammals: Part 3

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  1. Marine Mammals:Part 3 Marine Vertebrates: Lecture 9

  2. Cetacea OriginsArchaeocetes (~50 mya) • Pakicetus • Long, slender jaws • Simple teeth • Dorsal blowhole • Robust pelvis and hindlimbs

  3. Cetacea OriginsArchaeocetes (~50 mya) • Basilosaurus • More obviously aquatic • Reduced hindlimbs

  4. Order CetaceaSuborder MysticetiOverview • Baleen • Head • # of species • Location/ feeding Right whale baleen; photographer unknown

  5. Order Cetacea: Suborder MysticetiFamily Balaenidae • Large heads • Bowed (highly curved) mouth • Adaptive value? • Characteristics of baleen? • Fins • No dorsal • Small pectoral fins • Primarily known to feed on copepods • Feed by skimming

  6. Order Cetacea: Suborder MysticetiFamily Balaenidae: bowhead whale • Arctic • Follows cycle of ice • Most northerly Mysticeti • Hunting began ~1600, near extinction by 1900 • Slow recovery • Inuit hunting • Head may be up to 40% of body length • Baleen highly valued • Silky and Long Bowhead whale; artist unknown

  7. Order Cetacea: Suborder MysticetiFamily Balaenidae: Southern right whale • Callosities • Why called right whales? • Two species • Current status Southern right whale: Photo: Ocean Alliance

  8. Callosity close-up: Whale lice and barnacles on a right whale Photo: Iain Kerr Ocean Alliance Whale lice Photo: Vicki Roundtree

  9. Order Cetacea: Suborder MysticetiFamily Eschrictiidae: Gray whales • Where found? • Key Features • Relatively slender • Whale lice/barnacles • Throat grooves (2-7) • Bottom feeders • Method? Key food? • Migration • Once near extinction • Recovery • Removed from U.S. endangered species list in 1994 Gigi the Gray Whale Photo: Ron Church

  10. Order Cetacea: Suborder MysticetiFamily Balaenopteridae • Throat grooves: expansion during feeding • Depressed frontal bones • Small, posterior dorsal fin; flipper size varies • Relatively fast Humpback Whale,Photo: K. Haberman

  11. Order Cetacea: Suborder MysticetiFamily Balaenopteridae: minke whale • Worldwide distribution • To whale or not to whale? • Antarctic populations feed on…krill! • Northern pops feed on krill & fish Minke Whale, Project Atlantis

  12. Order Cetacea: Suborder MysticetiFamily Balaenopteridae: humpback whale • Worldwide distribution • Migrate cold water (feed) to tropics (breed) • Feed on krill and fish • Huge pectoral fins • Distinctive white patches • Scars, barnacles and cookie-cutter bites • Distinctive behaviors… • Conservation status: vulnerable • Hunted by Carib natives Humpback Whale Photo: H-C travel

  13. Whale songs • How produced? • Which ones sing? • Singing posture • Song length • Changes over time

  14. Order Cetacea: Suborder MysticetiFamily Balaenopteridae: blue whale Blue Whale Photo: Project Atlantis

  15. Blue whale facts • Distribution: Once worldwide; now largest populations are off coast of _____? • Migrate to tropical waters for calving • In some tropical areas, blue whales are seen year round • Why might this be? • Largest animal ever • Up to 24.5 meters (female); Mouth alone of 6 meters; 190 tons • Heart the size of a VW bug • Spray from blow is about 6 meters high. • Larger prior to mechanized whaling • Only hunted after the development of the grenade harpoon (1800s) • In one year, 30,000 were killed (not sure which year) • Loudest,deepest voice of any animal: 180 dB, 10 Hz • Diet is almost exclusively…???

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