marine mammals. order sirenia: manatees and dugongs 1 species dugong1 species dugong 3 species...
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Marine Mammals
Order Sirenia: Manatees and Dugongs
• 1 species dugong• 3 species manatees
Florida Manatee
• Endangered • Herbivore• Migrate in Winter• Inhabit tropical waters
Order Pinnipedia: Sea Lions, Seals and the Walrus
Family Otariidae: Sea Lions
• External ears• Long neck• Performs in shows• Pull hind flipper
under body• Claws ¾ to end of
flipper
Family Phocidae: Seals
• No external ears• Short neck• Back flippers to
swim• Can’t rotate hind
flippers• Claws at end of
flippers
Family Odobenidae: Walrus
• Use vibrissae (whiskers) to feed.
Order Carnivora: Sea Otter
Two North American Species
1. The Alaskan
2. The Californian
Prized for pelt
• Over 1 million hairs/in2
• Need thick fur because they have NO blubber
• Oil on hair to repel water
Oil Spills
• Oil covers fur and otters die of exposure• When otters attempt to clean their fur, they
ingest the oil and die.
Diet
• Eat invertebrates (urchins and abalone).• Use tools.
Order Carnivora: Polar Bears
• Well-developed claws, strong facial musculature, specialized teeth.
Family Ursidae
• Partially aquatic bears.• Inhabit arctic sea ice, water islands &
coastlines.
Adaptations to the Arctic
• Small ears which help conserve body heat.
• 12’’ paws – act like snowshoes• Non-retractable claw (to grip ice)• Thick fur• Fur is oily and water repellent• Skin is black which enables the bear
to absorb sunlight energy to warm its body.
• Have 4 inches of blubber
• Need 4.4 lbs of fat a day to survive. • Polar bears can smell a seal more than 20
miles away.• Feed mainly seals, but will scavenge other
mammals
• No natural predators as adults• Threatened species protected under MMPA (Marine
Mammal Protection Act)• No hunting in U.S., but are hunted in Canada.
Whales
Order: Cetacea
Suborders:
1. Mysticeti = Baleen whales
2. Odontoceti =Toothed whales
Whale Anatomy
• Female whales have a genital slit and 2 mammary slits.
• Males have 1 genital slit.
Order Mysticeti (Baleen Whales)• Largest: Blue• 2nd largest: Fin • Humpback (sings)• http://www.oceanmammalinst.o
rg/songs/hmpback3.wav
• 2 Blowholes
Humpback
Minke Whale
Baleen
• Used for filter feeding• Grow down from upper jaw.
Rorqual• Many throat grooves• Shorter baleen plates
• Expand capacity of mouth
Diving Adaptations• Have 2x the RBC’s, and 9x
the myoglobin (than humans)
• Countercurrent heat exchange system
• Veins surround arteries; heat from blood in arteries is transferred to venous blood.
• Mammalian diving reflex- blood is shunted away from extremities to vital organs.
Gray Whale
Undertakes the longest migration (11,000 miles)
•
Order Odontoceti• Examples: Sperm,
Orca, Dolphins, Porpoises, Narwhal & Beluga
• Found in fresh and salt water
• Many toothed whales are countershaded or have disruptive coloration (killer whale)
• Sperm Whales have teeth in the lower jaw only!
• One Blowhole• No sense of smell in toothed whales
• Largest member of Dolphin family is Orca
• Largest toothed whale is the Sperm Whale
• Fastest is Dall’s Porpoise: 34 m.p.h.
Sperm Whale Dall’s Porpoise
Orca
Cooperative Hunting• Orcas, false killer whales, pilot whales, & bottlenose dolphins• Hunt in packs like wolves • Humpbacks use bubble netting to surround
their prey
Echolocation• Enables toothed whales
to locate and discriminate objects by listening for echoes
• Uses organ called a melon which contains fats
• Acts as an acoustical lens to focus sound waves out to H2O
• Sound travels 4x faster in H2O than in air.
• Lower jaw bones = sound reception