Unit 9 Lesson 9.5
Marine mammals
Name
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Vocabulary:
Blubber: A thick layer of ___under the skin of many marine mammals that
provides_____________, ________ ____________ and ___________________ in the water.
Baleen: Plates of flexible, fibrous ____________________ found in the _____________ of
several whale species, used to strain ____________ ________________ (“krill”) from the
water.
Krill: Tiny ______________-________animals that are a major ____________ source for
some baleen whales.
Blow-hole: The ___________ or nasal openings of dolphins, ______________ and whales.
Lecture
Marine mammals
Sea otters
Polar bears
Pinnipeds
Sirenians
Diverse groups of ______ ___________ that have adapted to life in
the ocean: all have ____________, bear _____________ young and
_____________________ their offspring.
The sea otter is the smallest marine mammal and has no
________________ ___________; its insulation is provided by ______
trapped in its thick fur. Otters use tools like ___________ to crush
shells of _______________ and other shellfish. Otters help to keep
kelp forests healthy by eating _______ _____________, which graze
on kelp. This also helps to preserve the ____________________ of
the ocean ___________ ___________. Hunted for its __________ and
killed by fishermen, sea otter numbers declined in the 19th and
20th centuries.
Polar bears are ___________-______________ and spend much of
their lives on drifting Arctic _______. They feed primarily on
________, but also whale and walrus carcasses. Male polar bears
may grow to ____ ________ tall and weigh over _________ lb. while
females may reach ___________ feet and weigh _________ lb. Polar
bears have been known to swim ____ _________ at a stretch.
They are found in the Arctic, Alaska, Canada, Russia,
Greenland, and Norway. _________________ are their main
predators. Global warming threatens polar bear populations by
______________ __________ ________, which is their main habitat.
Seals, sea lions and walruses (pinnipeds) have paddle-shaped
______________ for swimming, but must _________ and _________
on land. “Blubber” is a thick layer of ________ for insulation, food
reserves and buoyancy. Many are pinnipeds are _______________,
which helps to conserve body heat in _________ waters. Elephant
seals are the largest: males can be _______________ and up to
more than ___________ lb. They can dive for up to ________ hours
without coming up for air! __________________ ______________ are
used for defense and to anchor the animal to the ice.
_____________________ and _________________ (sirenians), are also
known as “sea cows.” These gentle mammals are
_____________________ related to _______________________! They
are the only marine mammals that are _____________________
___________________________, feeding on ______ _____________ and
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Cetaceans
Baleen whales
Toothed whales
other vegetation. Manatees are larger, up to __________________
and over ________________lb. They have been aggressively
hunted by humans for their ___________-_______________
__________________ and meat. Sirenians have a low reproductive
rate, only one calf every ___________ years. Manatees are found
in the Atlantic Ocean, the Amazon, __________________ and South
Africa. Dugongs are only ________________ animals and are found
from East Africa to the western __________________ islands. Many
manatees have been injured or killed by collisions with ________
___________________in Florida; there are now ____________
_______________ restrictions in some manatee habitats.
Along with sirenians, the cetaceans, including _____________,
_________________, and ______________ have made the most
complete transition to ______________ __________, spending their
entire lives in the water. An example of convergent evolution,
these animals look very ______-_________, but they ___________
______, are ________-___________ and ____________ their young like
other mammals. They have front _______________ only, and some
have _____________ ____________ like fish.
Cetaceans have blubber for insulation and _________________,
but their __________ is almost absent. They have evolved
________________ on top of their heads called “________-________.”
Many cetaceans are highly ______________________; scientists
have studied their sophisticated _______________________systems.
The male humpback whale “songs” are thought to communicate
_____________________ _________________ and females can hear
these songs as far as ____________ miles away!
The _________________whales on earth are called “baleen whales,”
which refers to the _________________ __________________ in their
mouths. They eat _________________ amounts of tiny ______________________ animals called _______________. Baleen whales have
no ________________, but instead, rows of flexible
___________________plates made of ________________that hang
from their upper jaws. They ______________-___________by gulping
huge mouthfuls of water, squeezing it through the baleen
______________ to strain out __________food particles. Blue whales
are the ___________________ of the baleen whales and some of the
largest ______________________ ever to have lived on earth. They
can reach lengths of ___________________ feet and can weight up
to 140 tons, or _________________________ lb! If the average teen
weighed 140 lb, ___________________ teens would equal one blue
whale!
80 species are _______________ whales, which include
_____________________ and _____________________. These whales
have _____-________ teeth, depending on the species, and tend to
be ________________ than baleen whales. There are a few larger
species such as the killer whale and the mighty ________________
whale (“Moby Dick”), which can grow to ________________ feet
long.
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