Whales, Dolphins, Porpoises

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• Whales, Dolphins, Porpoises

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Phylum Chordata, Class mammalia, Order Cetacea
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Cetaceans are grouped on basis of their mouths

• Mysteceti - Whales with baleen (strainers) for
  plankton Both nostrils have a blow hole
• Odontoceti - whales, dolphins, and porpoises with
  teeth carnivores 2 nostrils but only one blow
  hole smaller in size

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Marine Mammal Characteristics

• Hair (at birth)
• Nurse Young
• Breathe Air
• Warm Blooded
• Placenta
• Horizontal Tail ( All marine cetaceans)

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The Blue Whale

• 100 feet long
• 150 tons
• The largest mammal alive.

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Narwhal

• The Tusk is an 8 foot left tooth and found only
  in males.

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Beluga Whales

• Pure white, Arctic whales. Called sea canaries
  due to their vocalizations.

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Dolphins

• The most intelligent whale.
• Body temp is a constant 97.7 F
• Average of 7 min. between breaths.
• Swims at 25 miles per hour.

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Whales and all marine mammals are protected by
the Marine Mammals Protection Act of 1972.
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Cetacean Adaptations

• In the Marine Habitat

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Swimming

• Powerful tail flukes
• Fluke markings are used as ID
• Sei whales are the fastest swimmers - 40 mph

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Digestion

• Multi-compartmentalized stomachs chew food.
  Teeth are conical and unspecialized.

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Digestion

• Baleen Whales feed by jumping through pockets of
  plankton (breaching)
• Stomach can hold 2 tons of krill at one time.

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Digestion

• Toothed whales often hunt in packs and seek out
  individual fish, penguins, seals, sharks or other
  whales.

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Cetacean II

• The Journey Continues

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Circulation

• High Blood volume holds max. oxygen and glucose
  levels. Their veins are large enough for a trout
  to swim through.
• Blood can be shunted to brain, heart , lungs and
  muscles and away from stomach and kidneys to
  protect vital organs.
• A 4 chambered heart can transfer arteriole heat
  to the veins as blood flows toward the tail
  called counter current heat exchange.

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Circulation Cont.

• Blubber insulates against cold. Overheating is
  solved by sending blood to surface tissues (
  flukes and fins) and bypassing the countercurrent
  vessels.
• Whales in captivity exercise less and often lose
  the ability to cool off by straightening the fins.

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Senses

• Vision is poor in most species
• Vocalizations and echolocation compensates.
• Whales have no vocal chords but make songs ,
  clicks and whines by vibrations in the blow hole.

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Communication

• Indicate territories
• Attract mates
• Act as homing device for young.
• Families of whales have their own dialect.
• Sounds are emitted and amplified in the head
  through an oil filled cavity called a melon.

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• Incoming vibrations are focused through the jaw
  and melon to the inner ear and the brain.
• The sounds are extremely accurate and very loud-
  can be used to stun prey.
• When whales enter the thermocline, sounds can be
  heard ¼ of the distance around the earth.

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Diving

• Lungs are completely filled and emptied quickly
  through the blow hole on top of the head.
• Trachea under the blow hole connects directly to
  lungs.
• Cannot breathe through their mouth and can drown
  unless the top of the head is exposed to air.

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• Nasal passage closes when relaxed to prevent
  water from entering the lungs, and allows them to
  sleep for short periods without drowning.
• Some whales go to depths of 13,000 ft. and only
  breath every 90 minutes smaller species have
  less range.
• Oxygen is stored in the muscles. Ribs are
  collapsible to reduce internal air pockets.

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Excretory

• Specialized kidneys allow whales to drink salt
  water. The urine is very saline.

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Reproduction

• Mating usually occurs in early summer.
• Implantation of the egg is delayed 4 months.
  Gestation lasts 7 months, so babies are born in
  warm summer months.
• Many whales only have one calf every 2-3 years.
  Babies range in weight from 200 pounds to 1 tone.

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California Grey Whale
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Humpback
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