Read the passage. Think about the meanings of the
There is a debate about the name sea turtles
Turtles tortoises and terrapins all belong to the same order. Tortoises live on
land, terrapins live in fresh water and turtles live in salt water. So, turtles
by definition should be sea animals! However some of the larger
freshwater varieties are also called turtles, so we will stick with the name Sea
Turtle, to save confusion.
They belong to the invertebrates and are reptiles. There
are seven known species of sea, or marine, turtle. They vary in size, the
largest being the Leatherback Turtle. We are going to look at the Green turtle.
All of the sea turtles have similar adaptations and similar problems.
The four limbs are flat and can be rotated, so as to
enable them to swim and move on land.
They have a heavy shell protecting most of their body.
The head can be withdrawn into the shell.
They lay their eggs in only a few places, always the same
They lay their eggs above the high water mark.
They swim fairly close to the surface of the water.
The structural adaptations really are not a drawback,
or problem. The weight of the shell means that they are clumsy and slow on land,
and so when the females go to lay eggs they can be easily caught. Other than
that, the structural adaptations tend to protect them.
The problem lies with the behavioral adaptations. The
fact that they always return to the same place to lay their eggs makes them vulnerable
to both human and other predators. People and other animals such as birds and
fish, know when the laying season is and where the eggs will be laid. The female
turtles struggle up the beach to a place above the high water mark. There they
dig a shallow pit with their fore flippers, and lie in it. The hind flippers are
then used to dig a deeper pit, into which the eggs are dropped. The number of
eggs varies but the usual amount is around 100.
The eggs are the covered over with sand and the female
returns to the sea. After sometime (from 48-80 days the eggs hatch. All the baby
turtles (known as hatchlings) get together and collectively make their way to
the top of the pit. They then wait for nightfall. After dark, they push out the
top of the nest and make a dash for the sea.
Because so many females lay their eggs in the same area, one will
often disturb the nest of another, while digging, and unintentionally
destroy the eggs.
Humans dig up the eggs immediately after they have been laid. They
sell them to restaurants. They are considered a great delicacy in some
Crabs, Monitor lizards and stray dogs will also dig up the nests.
Night birds. Crabs, lizards and dogs pick off the hatchlings
as they make their way back to the sea. The number lost depends to a great
extent on luck. If the hatch on a night with a low tide they have a long way to
go to get to the water line. If it is high tide, more will make it before being
If the hatchlings dont reach the water by sunrise other birds
will eat them.
Predatory fish (mostly shark) lie in wait just offshore at the
breeding grounds. They pick off the hatchlings as they make their way out to
It is estimated that the average female Green Turtle lays
about 1,800 eggs in her lifetime. Only about 400 of these actually develop and
hatch. Of those about 250 make it to the sea, and of those only about 30 will
survive their first week at sea.
Thirty offspring, per adult female seems like a good
number, but the story doesnt end there. Adult turtles are also attacked and
eaten by sharks, and even whales. They also suffer from disease and many are
killed by passing ships and speedboats. They are also hunted as food. The number
of hatchlings, per adult female who actually grow to complete a full life cycle
is probably about three. Again, that isnt bad; it is just about enough for
Green turtles to survive as a species.
However, there is a growing demand for turtle meat and
skin. This means that many adult females are being killed on the beaches. If the
trend continues, the Green turtles could well die out altogether becoming extinct.
Most places now have laws to protect the nesting beaches.
Neat Turtle Facts:
Turtle hatchlings are carnivorous, whereas adult turtle
are mostly vegetarian.
No one knows where turtles go during their fist year of
Females will swim thousands of miles from feeding grounds
to nesting beaches and back again.
The four main nesting beaches of ALL Green turtles are
found on the Costa Rican Coast, the Island of Ascension, the Seychelles and the
Great Barrier Reef.
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Exercise 1: Using Context to Define Words
Exercise 2: Word Puzzle
Exercise 3: Scrambled Words
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