Marine Mammals
Comparative Analysis
By Dr. M.
&
Mr. K.
Traits
1.) Most are viviparous.
2.) Have mammary glands which produce
milk to feed young.
3.) Young are usually altricial and need to be
cared for by parents for a while.
4.) Are endothermic.
Traits
5.) Most are carnivorous (not marine manatee).
6.) Have well developed organ systems, especially
the nervous system.
7.) Many are covered with fur, but some are not.
8.) Top feeders in Marine food chain.
PINNIPEDS
• Are fin footed mammals
• Are covered with fur
• Are excellent swimmers
• Are descendants of felines
Family’s of Pinnipeds
• True seals
• Sea Lions and Fur Seals
• Walruses
TRUE SEALS
• Have no external ears
• Hind flippers are permanently oriented
backwards
• Wiggle on their bellies on land and swim
via undulations of the body
TRUE SEAL
Fur coat
No external ear flaps
FLIPPERS
Seal molting clip
SEA LIONS AND FUR SEALS
• Have visible ears
• Hind flippers that can be rotated forward
for use as limbs on land
• Walk or gallop on land and swim via
powerful strokes of their front flippers
WALRUSES
• Have no external ears
• Hind legs rotate forward
• Only 1 species which lives in the artic
ocean
• Eat shellfish and krill
• Have tusks
• Have air sacs in neck that can be inflated
PINNIPEDS ON PARADE
PINNIPED DIET
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Most Pinnipeds eat:
Fish
Squid
Octopus
•Other invertebrates
PINNIPEDS ARE PREYED
UPON BY
• Killer whales
• White sharks
• Other large sharks
• Lice
• Internal parasites
DIVING ADAPTATIONS IN
PINNIPEDS
• Store oxygen in muscles
• Have more blood than land animals in proportion
to their body size
• Can direct blood flow to only vital organs
• Can slow heartbeat to use less oxygen
• Have a thick layer of blubber to protect them
from the cold
• Have bigger lungs
• Can slow metabolism
PINNIPED MATING
• Practice Harem Mating -a male defends a
stretch of territory and mates with many females
• Females give birth within the males territory
• Some males are excluded and live in bachelor
groups
PINNIPED MATING
• Giant Belligerent males mate with small
females
• Males engage in pushing, biting , and
bluffing contest
• Old males who lose disappear and are
never seen again
PINNIPED LIFE CYCLES
• Females give birth to 1 pup then leaves
the pup on land to feed at sea
• She returns once a week for a day long
nursing session
• Pups enter the water 4 weeks after birth
• Males leave the island 1st, then females
and pups leave in November for coasts
south
HOW PINNIPEDS BENEFIT
HUMANS
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Provide food
Retrieve missiles for navy
Retrieve traps and tools
Entertainment
WHAT IS A WHALE?
TRAITS OF CETACEANS
(WHALES)
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Mammary glands
Endothermic
Viviparous
Smooth skin
Blubber under skin
KINDS OF WHALES
• Odontecti - toothed whales
• Mysteceti - baleen whales
EVOLUTION OF WHALES
Characteristics of Odonteceti
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Conical shaped teeth
Smaller than mysteceti
Are carnivorous (eat fish, squid, etc.)
Can dive up to 2000 m
Can breath hold up to 90 minutes
Over 65 species
Sperm whale is largest toothed whale (65 feet)
Odonteceti continued
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Communicate while hunting
Live and travel in groups called pods
Some mate for life
Females and offspring travel in groups with last
year’s offspring
• Some older males live in bachelor groups
• Oldest males like Moby Dick live solitary lives
• May migrate - wintering near equator and
summering near poles
Traits of Odonteceti
Teeth of odonteceti
WHALES HUNTING
DOLPHIN AND PORPOISE
DIFFERENCES
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Dolphins
Have beaks
Conical teeth
4m in length
Extroverted
Sociable
Live in groups
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Porpoises
No beaks
Spade shaped teeth
Reach 2m
Introverted or in pairs
Dolphin and Porpoise
Differences
• Dolphin
• Porpoise
The family Dephinidae
includes
Pilot whales
Belugas
Killer Whales
Bottlenose Dolphins
FLUKESFLUKES
• Each lobe of the tail is a fluke
• Flukes have no bones or muscles
• Muscles of back and caudal peduncle
move flukes
• Spread of flukes=20% of body length
• Arteries and veins are oriented in a
countercurrent system
COUNTERCURRENT SYSTEM
Dolphin’s Head
• Well defined rostrum (snout)
• Conical interlocking teeth designed for
grasping
• 71-104 teeth
• Eyes are on the side of the head near the
corners of the mouth
• Ears are located behind the eyes. Small
openings with no external flap
DOLPHIN SENSES
• EXCELLENT VISION IN AND OUT OF
WATER
• Eyes have rods (black and white) and
cones (color vision)
• Skin is sensitive to touch
• Have taste buds
• No olfactory bulb, possibly no sense of
smell
DOLPHIN SWIMMING
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Regularly swim at 3 - 7 mph
Burst of up to 40 mph
Regularly dive 10 - 150 feet
Deepest trained dive up to 1,800 feet
Average of 1 - 6 breaths per minute
Dives can last 8 - 10 minutes
ADAPTATIONS FOR DIVING
• Heartbeat is reduced
• Blood is directed to vital organs (heart,
lungs, and brain)
• Muscles have myoglobin, which stores
oxygen and helps prevent oxygen
deficiency
Adaptations for diving
DOLPHIN RESPIRATION
• A dolphin exchanges 80 - 90 % of the air
in its lungs with each breath (humans
exchange 17%)
• Dolphins inhale and exhale in less than 2
seconds
• Water vapor is expelled through the blow
hole
DOLPHIN SLEEP
• Russian studies show that dolphins may
have deep sleep in one hemisphere at a
time.
DOLPHIN BODY REGULATION
• Body Temperature is 98.4 0F
• Body Fat is about 18 - 20 %
DOLPHIN SOCIAL
ORGANIZATION
• Live in groups called pods (2 - 20 in pods)
• Pods are based on age, sex, and familial
relations
• Mature females and offspring
• Mature males and sub adult males
• Hunt together in teams
• Have dating rituals and friendships
• Express emotion
Social Behavior
FOOD
• Eat fish, squid, and crustaceans
• Eat 4 - 6% of body weight daily
• Do not chew their food but swallow it
whole head first so spines won’t catch in
their throat
REPRODUCTION
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Gestation is 12 months
Worldwide calves are born all year
Usually give birth to 1 calf every 2 years
Calves are 42 - 48 inches and weigh 25 - 40 lb.
Calves may nurse for 12 - 18 months 2 - 3 hrs a
day 1 minute at a time
• Dolphin milk is 17% fat, 10% protein, 71% water.
(human is 4.5% fat, 1.1% protein and 87.4%
water)
ECHOLOCATION IN
DOLPHINS
• Air sacs - make clicks
• Melon - focuses clicks
• Lower jaw - detects returning sounds
ECHOLOCATION IN
DOLPHINS page 2
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Used to sense landscape in the dark
Used to locate prey
May be used to locate one another
May be used to stun prey
Works like sonar
Echolocation video
Echolocation in a Sperm Whale
A. Blowhole
B. Frontal Air Sac
C. Distal Air Sac
D. Monkey’s Muzzle
ECHOLOCATION
• Gives the whale a detailed picture of the
seascape
• Allows whales to dive to depths of 2,000
meters to locate prey and avoid injury in
total darkness
ECHOLOCATION IN SPERM
WHALES
• Clicks are generated by a pair of hard lips tightly
compressed inside the skull called the monkey’s
muzzle
• Sound is focused by an oil filled organ inside the
head called the spermeceti organ (occupies
40% of whale length) once used in oil lamps and
helps adjust density in the sperm whale
• Returning sounds are received by the lower
jawbone and processed by the nervous system.
ECHOLOCATION IN SPERM
WHALES
Dolphin Intelligence
• Have a brain structure similar to humans
• Can process the complexities of social
relationships when living in organized
groups
• Have a large number of interconnections
between neurons
INDICATIONS OF DOLPHIN
INTELLIGENCE
• Can learn languages and respond
correctly to sentences never uttered to
them before ex. Frisbee fetch hoop
• Can rearrange environment to follow a
command ex. Swim through a hoop, but
hoop is on the bottom of the pool
TRAITS OF MYSTECETI
(BALLEEN WHALES)
• Have baleen instead of teeth
• Are larger than toothed whales ex. Blue whale is
100 feet long and weighs 300,000 lbs. - Largest
animal on earth
• Have 2 blowholes
• Ribs are are not attached to sternum
• Invent own stunts
• Play competitive sports
HUMPBACK WHALES
• Eat enough in summer to last rest of the
year
• Hunt together creating bubble nets to drive
schools of fish close together and then
swim up from underneath
• Communicate over long distances
• Males sing long songs over and over
again to attract females
• Breach, lobtail, and spyhop
HUMPBACK WHALES
BLUE WHALE
BALEEN
Baleen Whales Documentary
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Marine Mammals - Great Neck School District