DOLPHINS
By
(5th Grade)
Biome
• Dolphins live in the Aquatic Biome.
• This biome can be broken down into two basic regions:
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Freshwater and Marine
The bottlenose dolphin is found worldwide in tropical and
temperate marine ocean waters.
The largest of all the ecosystems, oceans are very large
bodies of water that dominate the Earth’s surface.
Biome
• Bottlenose Dolphins live in the pelagic zone of
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the ocean, which includes those waters further
from the land, basically the open ocean.
The pelagic zone is generally cold.
Biome
• The flora in the pelagic zone
•
include surface seaweeds.
The fauna include many
species of fish and some
mammals, such as whales
and dolphins.
Many feed on the abundant
plankton.
Habitat
• Bottlenose dolphins are found from northern
•
Japan and California to Australia and Chile and
in worldwide oceans.
Bottlenose Dolphins can be found in harbors,
bays, lagoons, gulfs, and estuaries.
Food Chain
• Tiger, Bull and
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Dusky Sharks are
the main predators.
They also get caught
in fishermen’s nets
as they fish for tuna.
Dolphins are hunters
and they mainly eat
fish and squid.
They hunt near the
surface of the water.
• Dolphins are not fish;
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•
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they are considered
mammals.
They breathe air directly
into their lungs.
They are warm-blooded.
They give birth to live
young.
They are like small
whales, and can swim
more than 25 miles per
hour.
They have 94 teeth and
they travel in groups
called pods.
Interesting Facts
Bottlenose Dolphin
Behavior
• They are known for their
•
•
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playful behavior.
They can jump 20 feet.
When hunting they chase fish
toward shallow water.
They corral schools of fish and
take turns swimming into the
school to feed.
Watch this video.
Bottlenose Dolphin
Behavior
Structure and
Function
• Stream-lined bodies
and a rounded head
with a distinctive beak.
• They have a tall, falcate
(sickle-shaped) dorsal
fin and broad, slightly
pointed flippers.
• Use their tail flukes
• Melon is fatty and helps direct
sound.
when hunting, by hitting
a fish up into the air
with their tail, stunning
it, then scooping the
fish up when it falls
back into the water.
Communication
• Dolphins use snaps and whistles to warn other
dolphins of predators.
Adaptations to Survive
• Bottlenose dolphins have a
layer of blubber under their
skin to keep warm.
• During a deep dive (up to
1000 feet) their lungs and
ribs partially collapse.
• They store oxygen in their
blood and muscles instead of
their lungs.
Evolution
• Inside their pectoral fins, dolphins have a
skeletal structure similar to a human arm and
hand.
• They have a humerus with a ball and socket
joint.
• They have a radius and ulna, as well as a
complete hand structure, including five finger
bones.
• This makes scientists think dolphins evolved
from a terrestrial ancestor.
Evolution
Diagram of a
dolphin dorsal fin
bone structure
and a human arm
and hand bone
structure.
Life Cycle
• Bottlenose dolphins breed in early March
to mid May.
• Baby dolphins grow to an adult dolphin
and then reproduce.
• Dolphins can live up to
twenty five years
in the wild.
Reproduction
• When dolphins mate, they
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don't really get married.
They just swim belly to belly
for about 30 seconds.
The average time a calf grows
inside a mother is about 10-12
months.
Calves have to be born tail
first otherwise they will
probably drown before they
are able to fully come out of
their mother.
Reproduction
• After the two dolphins mate and have their baby,
they part, and the mother dolphin takes care of
the baby by herself.
Babies
• When they are born, dolphins have whiskers on
their rostrum.
• A dolphin’s whiskers are about one quarter inch
long, and will fall out after birth, because of
water pressure.
• Babies stay with their mom 3-6 years.
Human Impact
• Bottlenose dolphins have been
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caught for meat, leather, oil, and
meal (for fertilizer and animal feed).
Are affected by pollution, heavy boat traffic,
habitat destruction, and competition for schools
of fish by fisheries.
• Caught accidentally in fishing nets. Recent
conservation efforts have greatly reduced the
number of dolphin deaths. But scientists believe
that actual deaths may be more than reported.
References
Photos used with permission and retrieved from:
http://www.pics4learning.com
Video used with permission and retrieved from:
http://www.nationalgeographic.com/kids/creature_feature/0108
/dolphins2.html
Facts:
http://www.dolphins.org/Learn/lmm-phys.htm
http://www.enchantedlearning.com/subjects/whales/
species/Bottledolphin.shtml
http://www.aqua.org/downloads/pdf/Dolphins.pdf
Kovacs, Deborah. All About Dolphins! Bridgeport, Connecticut:
Third Story Books, 1994.
Gay, Tanner Ottley. Whales and Dolphins in Action. New York:
Aladdin Books, 1991.