Marine Mammals

Marine Mammals
Erwin R Ardli
Return to the Oceans
Mammals have returned to the oceans multiple
times
Adaptasi
• vivipary
• suckling young
• thermoregulation
• feeding
• diving
• osmoregulation
We’ll look at adaptation in marine
mammals from the least to the most
Adaptations for diving
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Exchange a large amount of air on each breath
Up to 90% in each breath (humans exchange about
20%)
Blood with more oxygen carrying capacity
Heart rate slows
Blood flow shunted
Higher concentration of myoglobin in the muscles
Collapsing lungs
Dive with no air in contact with blood vessels to avoid
problems of nitrogen being forced in
Fusiform Shape and Streamlining
Evolutionary Convergence
Two basic bioenergetic
strategies used by animals :
• Endothermy “warm blooded”
• Ectothermy “cold blooded”
Countercurrent Exchange
Concurrent exchange
Countercurrent exchange
Marine Mammals
Marine Mammals
Marine mammals
 Karakteristik:
Warm-blooded
 Breathe air
 Have hair (or fur)
 Bear live young
 Females have mammary glands that
produce milk for their young
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Marine mammals: Order Sirenia
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Sirenian characteristics:
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Large body size
Sparse hair all over body
Vegetarians
Toenails (on manatees only)
Includes:
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Manatees
Dugongs
Manatee & Dugong
• Most complete transition to marine life
along with whales and dolphins
• Related to the elephant, but common
ancestor didn’t look like either of them
• Once many more species around
• Large layer of blubber
• Origin of the mermaid myth
• Herbivores
• Nostrils on top of snout have valves to
keep water out
• Both species have one calf at a time
• Tend to have a single calf every 3 years
Dugong
Location: coastal and inland waters
of the western Indo-Pacific region
• Dugongs are exclusively marine
and have a dolphin-like tail
• Dugongs tend to dig seagrass
rhizomes
• Predator includes tiger sharks
10,000
Dugong Range
Family Dugongidae
Dugong dugong
8.9 ft, 551-661lbs
Steller's Sea Cow
tHydrodamalis gigas
Discovered 1741,
extinct 1768.
30ft, 4.4 tons
Manatee
Location: Florida, Central and South
America
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Manatees have paddle-like tails
and frequent freshwater
Manatees tend to crop and grab
with prehensile lips
Manatees are larger than dugongs
Few predators
Threats:
• Careless boaters
• Habitat loss
Manatee
9.8 ft, 800-1200lbs
3,000 in U.S.
Relationship
between Sirenians
and elephants
(mtDNA)
Asian elephant
African elephant
tmammoth
tmastadon
tStellar’s
sea cow
Dugong
Ancestral
mammals
West Indian manatee
Brazilian manatee
West African manatee
Other mammals
80
60
40
20
Million of years before present
0
Marine mammals: Order Carnivora
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All members of order
Carnivora have
prominent canine teeth
Includes:
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Sea otters
Polar bears
Pinnipeds (flipper-footed)
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Walrus
Seals
Sea lions/fur seals
Hawaiian Monk Seal
Sea Otter
Sea Otter
• Enhydra lutris
– Native to north Pacific
– 394,000 hairs/cm2
– No blubber
– Female 45 lbs; Male
65lbs
– Diet: Sea urchins,
abalone, mussels,
clams, crabs, snails
and about 40 other
marine species.
– Uses tools
– Dives to 330 ft
– Rests in coastal kelp
forests
Polar Bear
Pop size: 22,000 to 27,000
Weight: 550 to 1,700 pounds
Polar Bear
• Ursa maritimus
– United States, Canada,
Russia, Greenland and
on the Arctic islands of
Norway
– Male: 10 feet tall and
weigh over 1400 lbs
– Female: seven feet
and weigh 650 lbs
– wild polar bears live up
to age 25.
– Good swimmers
– Thick blubber
– Thick fur
Polar bears
• Polar bears are the least
adapted to the marine
lifestyle
• Land animals that are
adapted to the cold
• Considered marine mammals because they feed
almost exclusively on marine organisms
• Very good swimmers, but can’t dive below
surface well
• Hunt seals and walruses, occasionally cetaceans
Range:
• Circumpolar in Arctic
• Range depends on sea ice
• normal range
occasional range over pack
occasional range over permanent ice
Pinnipeds
Pinnipeds
Hawaiian Monk Seal
Family Phocidae
Walrus
Sea Lion
Family Otariidae
Family Odobenidae
Biology and Natural History
Order Pinniped (seals, sea lions, & walruses)
Family Phocidae- true, earless seals
Family Otariidae- eared seals and sea lions
Family Odobenidae- walruses
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34 known species
Evolved 20 mya from Order Carnivora (ancestors of dogs
and bears)
Differ in possession of external ears and mode of
locomotion
Differences between seals and sea
lions/fur seals
Hawaiian Monk Seal
Family Phocidae
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Lack external ears
Hind flippers propel them while swimming
Front flippers act as rudders
Travel on land is difficult (wiggle)
Sea Lion
Family Otariidae
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Eared seals
Front flippers propel animal when swimming
Rear flippers act as rudders
Fairly mobile on land
Walrus
Family Odobenidae
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Found in Arctic region
Lack external ears
Paddle with front flippers
Rear flippers act as a rudder
Fairly mobile on land
Walrus Range Map
Pacific walrus is in lavender, Atlantic walrus is
in rose.
Walrus Facts
Location:
• Bering sea, Pacific Ocean, Atlantic Ocean, Arctic Ocean
Pop Size:
• 250,000
Size:
• Weight: 2,000-3,500 lb.
Breeding:
• Sexually mature late
- females, usually 6-7 years
- males, 15 years.
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Produce few offspring
Walrus Facts
Lifestyle
• Habit: Gregarious, living mainly
in herds.
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Diet: Benthic suction feeders.
Feed mainly on bivalve
mollusks, but also other
invertebrate marine animals,
fish, sometimes seals and
whales.
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Predators: polar bears, killer
whales, and humans
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Lifespan: Up to 40 years.
Walrus Facts
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Swim speed: 7-35 kph
Tusks:
- Both male & female
- Used for dragging body across land or ice
- Symbolize age, sex, and social status
Pharyngeal pockets:
- 2 found on either side of the esophagus that hold up
to 50 liters of air ).
- For buoyancy; these pockets facilitate sleep in the
water in an upright position
- May be used to amplify mating calls
Whales, Dolphins,
& Porpoise
Pakicetus attocki
Age: Early Eocene, 50 million years old
Location: Pakistan
Whale Evolution
Ambulocetus natans in action. A reconstruction of an early
close cousin of whales.
Marine mammals: Order Cetacea
Marine mammals: Order Cetacea
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Cetacean characteristics:
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Blowholes on top of skull
Skull telescoped (streamlined shape)
Very few hairs
Includes:
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Whales, dolphins, and porpoises
Two suborders of order Cetacea
(55 mya- entered sea)
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Suborder Odontoceti (toothed whales)
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Echolocate (send sound through water)
Includes killer whale, sperm whale, dolphins,
porpoises, and many others
Suborder Mysticeti (baleen whales)
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Have rows of baleen plates instead of teeth
Includes blue whale, finback whale, humpback
whale, gray whale, and many others
Differences between dolphins and porpoises
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Dolphins have:
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An elongated snout
(rostrum)
A sickle-shaped (falcate)
dorsal fin
Conical-shaped teeth
Killer whale
jawbone
Differences between dolphins and porpoises
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Porpoises have:
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A blunt snout (rostrum)
A triangle-shaped dorsal fin
Spade-shaped teeth
Echolocation
• Sensing environment
• Produce clicks that travel out, hit
objects and reflect back
• Produced by a structure in the airway
called the “monkey lips”
• Sound received through the lower jaw
• Low frequency clicks travel further but
can only be used for big objects
• High frequency clicks can discriminate
small objects but don’t travel as far
Deepest Diver
(3km~1.5 miles)
Mysticeti: The baleen whales
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Mysticeti whales have baleen instead of teeth
Baleen plates:
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Hang as parallel rows from the upper jaw
Are made of keratin
Are used as a strainer to capture zooplankton
Allows baleen whales to eat krill and small fish by the ton
Baleen
Types of baleen whales
Baleen whales include three families:
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Gray whale (a bottom-feeder with short baleen)
Rorqual whales (medium-sized baleen)
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Balaenopterids (blue whales, finback whales, and other
large whales )
Megapterids (humpback whales)
Right whales (surface skimmers with long baleen)
Whale Migration
Whale Carcass Removal
http://perp.com/whale/video.nc.html