Marine Mammal Orders
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Pinnipedia – seals, sealions, walrus
Carnivora – sea otter and polar bear
Sirenia – Manatee and sea cow (dugong)
Cetacea - dolphine, porpose, and other whales
• Mammals have mammary glands, endotherms, 4 chambered
heart, have hair/fur, and most are viviparous (placental). Fur,
low surface-area to volume ratio, and blubber to maintain heat
and buoyancy.
Carnivores
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Sea Otters: Life in water - even giving birth.
Groom fur to trap heat. 100,000 hairs cm2
Keystone specie in kelp beds.
Eat 30% their weight of urchins, shellfish, and
crabs daily. 3x faster metabolism for heat.
• Orcas ate over 40,000 otters in 100 years.
• Polar Bear (means “arctic”):
spend most of their life in water traveling from
ice sheet to ice sheet, which are now scarce.
• Eat seals. Ferocious hunters stomp on dens.
• Arctic is the word for polar bear. Antarctica
(south) is where polar bears do NOT live.
• Still hibernate in dens.
• Have 2 cubs per year.
Sea Otters
• Sea otters spend the majority of their
life in the water. They even sleep and
always eat in the water.
• They must keep their feet out of the water to stay warm.
• They use rocks as tools to open shellfish.
• Sea otters must eat 25 percent of their body weight each
day in order to stay alive.
• Otter fur has 350,000 hairs per square inch. 1 4in. by 4
in. section is equal to 48 human heads of hair
• They nearly went extinct from fur traders. Now they are
legally protected, but the Orca whale just discovered
how tasty they are.
• Out of 16,000 otters living in the spill
zone, 1000 died, 400 were treated, but
only 200 were able to be returned to the
wild. The oil also killed 37,000 birds.
• It harmed 1000 miles of shoreline and
the entire food chain.
Sea Otters and Oil Spills
• When a sea otter's fur was oiled, the fur can no
longer hold the protective air layer that keeps
them warm so they die.
• Oil spill caused reproductive failure in sea otters
and many juveniles died from oil in their food.
Pinnipeds
• Seals: paddle-foot. Rest
on land, swim under water
up to an hour.
• Baby seals have white fur
for warmth and camo.
• More than one den to protect.
10 days then water.
• Evolved from “cat” and “dog”.
• Seals strain krill with teeth.
• Sea lions have ears, external
genitalia, and can move back
flippers forward.
• Walrus uses tusks for defense
and vibrissae (feelers) to find
and suck up clams. Blush to
release body heat.
Sirenia
• Manatees
There are 1000 left.
• Most killed by boats or
lack of sea grass.
• Front flippers and no legs. Just a tail with flukes.
• Humans hunted for meat, skin, and oil in blubber.
• Harmless and curious.
• Named after mermaid songs.
• Descended from elephants.
• One calf every 3 years. Males are not mature until 9.
Cetaceans: Whales
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Warm blooded. 4 chambered heart. Placental (live) birth.
Internal mammary gland and genitalia.
Can dive 2 miles deep and grow
Developed echolocation through modified ear and jaw bone.
Vestigial hair and pelvic bones present in embryonic stages.
Why have them if you don’t use them?
• Transitional stages in fossil record.
• Convergent Evolution of analogous features: flippers, flukes,
and streamline body (different make up, but similar function.
• Homologous structures: same make up, but work very
differently. Same bones as our hand, but shaped into a
flipper.
Convergent Evolution
Analogues Structures
Homologous Structures
Vestigial Structures
30 meters (90 feet) Largest Animal EVER!
Feeding
• Baleen whales eat plankton,
krill, and small schooling fish
that they filter with their
baleen (made of keratin).
• Toothed whales may eat
larger fish and mammals,
such as seals.
• Killer whales (orca) splash
large waves on ice bergs to
wash seals off into the water
where the pack of whales are
waiting to feed (on you-tube).
Rorquals with Throat Grooves
Echolocation
• Sperm Whale (Moby
Dick): sailors used to
think the enlarged
head contained
sperm.
• Now we know it is full
of oil (ambergris)
used for echolocation.
• Used in place of smell
Echolocation
• Melon: head full of oil.
• Spermatocie is the oil within the melon.
• The oil is also used for buoyancy and to absorb
extra nitrogen
• Lower jaw bones are filled with oil to transmits
sounds to the inner ear chamber.
• This produces an image similar to sonar
• It can also send a shock wave “Big Bang” to kill
their food
Arctic Beluga Whales
Dorsal ridge instead of fin (dorsal fins
causes heat loss
and would get stuck on ice).
You can watch their bulging melon can
change shapes during echolocation
Calves are born gray and lighten with age.
Vocalization
• Separate from echolocation
• They communicate to each other through sounds “clicks”,
“chirps”, and touching
• Used to maintain distance
• They recognize each other by sound
• Feeding signals and alarms
• They also say hi and play with bubble rings
• Whales sing to attract mates
Dolphin Swim
Dolphins and whales may swim up to
30 mph. Dolphins jump out of the water
to breathe when speeding.
They do tricks for fun and are
conditioned with rewards.
Very playful, but can attack with
rostrum.
Hunt in packs.
Cognitive Ability: http://library.thinkquest.org/17963/genus-Tursiops.html
Hydrodynamics–Dolphins swim fast!
Cetacean Breathing
• The nose of this order of marine mammals has
been adapted into a blow hole which is located
at the top of the head.
• Either one or two nostrils that can clamp shut to
prevent water from entering.
• They are conscience breathers so only half of
their brain can shut down at a time. They
laterally sleep with one eye open and half a
brain a wake. Then they rotate to the other side
for the next 8 hours.
Blood and Oxygen Storage
• Dolphins have larger lungs than humans and
can hold their breath much longer. They can
dive for 1 hour.
• 15 to 25% air exchange in human compared to
80 to 90% air exchange in whales
• They store 10 to 30 x more oxygen than us.
• They have 2 x more blood per pound in whales
than humans
Adaptations for Diving
• Diving down 2 miles (7,300 ft)
for food and protection for 1 h.
• Blood vessels in tongue reduces heat loss
• 90% gas exchange in one breath (20% in us)
• 3000 times more air than humans
• More red blood cells with more hemoglobin
and myoglobin (in muscles) to store oxygen
• Heart rate drops to 12 instead of 85 beats/min.
• Blood is directed from fins to vital organs (brain and
heart) only to maintain body heat at ocean depths.
Avoiding the Bends
• Nitrogen dissolves into the blood
under high pressure, but upon
surfacing it sends deadly bubbles to
the brain and joints (painful) like
carbonation in a 2 liter.
• Divers must go into a decompression
chamber if they are lucky!
• Whales’ flexible lungs collapse under
the water’s pressure squeezing out all
of the air so that nitrogen cannot get
into the blood stream and forces
oxygen into central body cavities.
Blubber
• 20 inches of blubber in Bay Whale
• Blubber retains body heat and prevents
melting ice because it keeps the heat
within the body (insulates). Your body can
loose heat twice as fast in water.
• Blubber also helps buoyancy.
• Whales stay warm by redirecting blood
away from the thin flippers and keep it
near the core of the body to stay warm.
Behavior
• Whales and dolphins will protect by attacking
with rostrum. They even spy.
• They will surround, support/carry, and stay with
their dead and dying until they rot.
• Hierarchy among pod (family) members.
• Monogamous partners. If one partner dies the
other may stop eating.
• Dolphins are one of the only animals to find
pleasure in intercourse. They have been to
reported to have been aroused by humans and
rape sharks.
Breaching
• Whale species can be
identified by the size
and shape of their
blow spout
• They breach to look
for landmarks and
danger
• warning signal
• Find fish
• fun and itch
Migration
• Gray Whales stay in the feeding grounds
for about four months moving south in late
September and early October (Watson
1981).
• The second habitat is the breeding
grounds off Baja California.
• There, Grays vacation in the 71-degree
waters where they give birth and keep the
calves warm for enhanced survival.
Reproduction
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Bachelor and harem groups.
Penis can exit genital slit 9 ft.
A second props the couple together.
Delayed Implantation of the zygote for up to 4 months
until female gets to the nesting ground.
12 month gestation - calf born where conceived.
Females give birth alone while guys hit on the next
ladies
Calves are nursed for 8 months and then migrate
Calves are weaned when they reach the Arctic
Raising the Young Whales at Sheds
• Baby beluga whales are gray because they live in estuaries not
within the white ice. This skin will slough off to white by the
time it will migrate north to the ice.
• At Sheds scientists were studying the biological processes of the
baby whale, such as, when they go potty, breathing rate, growth,
and socialization. She has gained 200 lbs. in 2.5 months. They
compare these statistics with past success of captive bred whales.
Dominance within the pack and submissive behaviors (such as
sharing food with others) are dangerous. Dominance is
displayed by jaw popping and charging.
• Their dorsal fin has been modified into a ridge so they can swim
closer to the surface (beneath the ice) to obtain oxygen and to
break up ice sheets.
• They act like canaries and can mimic sounds. At Shedds, one
whale mimicked the sound of the broken washing machine.
Psychology
• The cerebrum makes up a large proportion of brain used
for sensory interpretation, thinking, and memory.
• Conditioned learning: practiced behavior is
“trained” or reinforced with reward.
• Recognize sounds, symbols, & sign language
• Complex messages to communicate in pod,
hunt in packs, and adlib responses to trainers
• Discover and use tools in nature (protection)
• Learn by observation-mimic other animal
and human behavior with sound effects!
• Perform cognitive tests. Identifying self in
mirror by picking up an object.
• Recognize each other by sound
• They learn more from peers than parents
Beaching
• Unknown reason
•They refuse to move
•Efforts to put them back in the
water usually fail because the
whale re-beaches
•They think it is a problem with their
magnetic compass
• On land their weight crushes their
internal organs
Whale hunting
• One whale is worth $100,000.
• Whale oil: Before petroleum was discovered, whale oil
was the primary fuel for lamps. It could also be used to
make candles. Whale may be used in cosmetics,
• Whale vomit (ambergris) the size of a base ball is worth
$18,000 dollars because it is used in perfumes.
• Before we had plastic, the baleen was used to make
corset stays, combs, house rafters, and even buggy
whips.
• In the old days the Eskimos used to eat and use every
part of the whale.
• The human being has killed 90-95% of many whale
families. Others are already extinct.
Harpooning over 100,000 Whales in 2005!
International moratorium banned commercial whaling over 20 years ago. The Japanese
are exploiting a loophole (whaling for scientific research). Greenpeace was attacked!
Dolphin Safe Tuna - not so safe!
• Contaminants
(pesticides, metals,
plastics, etc.)
accumulate in the
tissue of dolphins.
• Injuries or deaths due
to boats.
• Fishing nets –
especially TUNA even
most “Dolphin Safe”
tuna now.
Dolphin Attacks in Japan
• Thousands of dolphins are slaughtered
annually in Japan. Females are taken
for display and the males are killed for
a $10,000 reward (each). The
Japanese claim they are depleting their
fish.
• They feed the dolphin meat to their
school children. It contains high levels
of mercury.
• Celebrities tried to stop them.
They almost got thrown in jail
for a VERY long time.
Whales
Blue whale
Right whale
• http://www.scienceandsociety.emory.edu/scienceinyourlife/cetacean
s.htm
• http://www.spawar.navy.mil/sandiego/technology/mammals/animals.
html
• http://www.acsonline.org/factpack/whlparts.html
• http://crd.dnr.state.ga.us/content/displaycontent.asp?txtDocument=3
65
• http://www.nmfs.noaa.gov/pr/species/turtles/leatherback.htm
• http://www.biologycorner.com/bio3/notes-chap16-evidence.html
• http://en.wikipedia.org/wiki/Dolphin
• http://bss.sfsu.edu/holzman/courses/Fall99Proje
cts/greywhale.htm