1. © 2011 Pearson Education, Inc.
Marine Mammals
 Land-dwelling ancestors
 Warm-blooded
 Breathe air
 Hair/fur
 Bear live young
 Mammary glands for milk

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Major Marine Mammal Groups

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Order Carnivora
 Prominent canine teeth
 Sea otters
 Polar bears
 Pinnipeds
 Walruses
 Seals
 Sea lions
 Fur seals

4. Polar Bear, Pittsburgh Zoo and Aquarium

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Carnivora

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Seals vs. Sea Lions and Fur Seals
 Seals lack prominent
ear flaps
 Seals have smaller
front flippers
 Seals have fore flipper
claws
 Different hip
structures
 Different locomotion
strategies

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Order Sirenia
 Herbivores
 Manatees
 Coastal areas of tropical
Atlantic Ocean
 Dugongs
 Coastal areas of Indian
and western Pacific
Oceans

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Order Cetacea
 Whales, dolphins, po
rpoises
 Elongated skull
 Blowholes on top of
skull
 Few hairs
 Fluke – horizontal
tail fin for vertical
propulsion

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Order Cetacea

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Order Cetacea
 Adaptations to
increase
swimming speed
 Streamlined
bodies
 Specialized skin
structure
 80% water
 Stiff inner layer
 Narrow canals
with spongy
material
Mr. Bantay at Discovery Cove, Florida (November 2011).

12. Discovery Cove, Florida. November 2011

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Order Cetacea
 Adaptations for deep diving
 Use oxygen efficiently
 Able to absorb 90% of
oxygen inhaled
 Able to store large
quantities of oxygen
 Able to reduce oxygen
required for noncritical
organs
 Muscles insensitive to
buildup of carbon dioxide
 Collapsible lungs

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Order Cetacea
 Suborder Odontoceti
(toothed)
 Dolphins, porpoises, kill
er whale, sperm whale
 Echolocation to
determine distance and
direction to objects
 Determine shape, size
of objects

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Dolphins vs. Porpoises
 Porpoises
 Smaller, more
stout body
shape
 Blunt snout
 Triangular,
smaller dorsal
fin
 Blunt or flat
teeth
 Dolphins
 Larger, more
streamlined
shape
 Pointy teeth
like killer
whales (orca)

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Echolocation
 Good vision of marine mammals is limited by ocean
conditions.
 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).

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Echolocation
 Toothed whales send sound through water.
 Sound is reflected, returned to the animal, and
interpreted.
 An evolved inner ear structure may help toothed whales
pick up sounds.
 Increased marine noise pollution may affect cetacean
echolocation.

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Echolocation

19. Sofar -Sound Frequency and Ranging channel
Underwater sound is used by many marine animals to sense their
environment, communicate, and find food. Underwater sound is also used by marine
scientists to measure ocean depth, track objects in the water, and determine ocean
temperature changes. Transmission of sound in the ocean is affected by water
temperature, pressure, and salinity. The normal variations in these properties with depth
combine to produce a minimum sound speed at a depth of about 1,000 meters. At this
depth, sound travels relatively slowly compared to the speed of sound through water at
greater and lesser depths. The depth zone centered around this level of minimum sound
speed is called the Deep Sound Channel, and is also known as the SOFAR (sound
fixing and ranging) Channel. Sound entering this layer tends to be trapped and
channeled along it, making this layer extremely efficient in transmitting sound for
thousands of kilometers through the ocean.

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Intelligence in Toothed Whales
 Large brains
relative to body
size
 Communicate
with each other
 Trainable

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Order Cetacea
 Suborder
Mysticeti
 Baleen whales

22. Blue Whale, NYC Natural Museum
Order Cetacea
 Blue whale, finback whale, humpback whale, gray
whale, right whale

24. Right Whale

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Use of Baleen
 Fibrous plates of baleen sieve prey items
 Vocalized sounds for various purposes

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Gray Whale Migration
 22,000 km (13,700
miles) annual
migration from coastal
Arctic Ocean to Baja
California and Mexico
 Feeding grounds in
Arctic (summer)
 Breeding and birthing
grounds in tropical
eastern Pacific (winter)

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Whales as Endangered Species
 Fewer whales now than
before whaling
 International Whaling
Treaty
 Hunting of gray whale
banned in 1938
 Gray removed from
endangered list in 1993
as population
rebounded

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Gray Whale Friendly Behavior

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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