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SCALY-SKINNED ANIMALS such as alligators, turtles, and
snakes are called reptiles. Some reptiles live in water and some
on land; most are found in the warmer parts of the world.
There are six main groups; lizards, snakes, worm lizards,
turtles and tortoises, crocodiles and alligators, and tuataras.
Tortoises and turtles are the only reptiles with shells. Lizards
make up the largest group, with about 5,500 different kinds,
yet there are only two kinds of tuatara. Reptiles are among the
most ancient of all animals. The first reptiles appeared around
300 million years ago. Crocodiles evolved more than 120 million years
ago, earlier than many dinosaurs. Today, there are more than 9,400
kinds of reptiles, from the long reticulated python, measuring 33 ft
(10 m), to the tiny dwarf gecko, only 1.3 in (33 mm) in length.
Unlike warm-blooded (endothermic) mammals, reptiles are cold-
blooded (ectothermic)—they need the warmth of the sun to
give them the energy to move.CRoCoDILIANS
Alligators, crocodiles, caimans, and
gharials are known as crocodilians.
There are 13 kinds of crocodiles,
two types of alligators, six kinds
of caimans, and two kinds of
gharials. The saltwater
crocodile is the largest
living reptile, reaching
22 ft (7 m) in length.SNAKE
Most snakes can
swim and climb well,
and move swiftly over
land even though they
have no limbs. The
venomous (poisonous)
African mambas, measuring
more than 6 ft (2 m) in
length, are among the fastest
snakes, with a top speed of
about 10 mph (16 km/h).LIzARD
With their slim, agile bodies and
sharp claws, lizards can scurry into
a crack or under a stone when
disturbed. Lizards are a familiar sight
in warm countries, where they are
most active by day.WoRM LIzARD
The worm lizard is an almost blind
reptile that measures about 3–24 in
(8–60 cm) in length. It detects its prey
of insects, worms, and small
vertebrates by sound and smell.ToRToISE
The tortoise is a turtle that lives on land.
Some tortoises live to more than 100
years old. The largest tortoises are the
Aldabran giant tortoise and the
Galapagos tortoise, which can grow up
to 4 ft (1.2 m). The smallest is the
speckled Cape tortoise—males of this
species grow up to only 4 in (10 cm).CrocodileTuataraTUATARA
Both species of tuataras are found
only on a few New zealand islands.
They are in danger of extinction
and are now protected species.
The tuatara has hardly changed for
thousands of years—it looks very
similar to fossils 140 million years
old. Tuataras are about 2 ft
(61 cm) long and feed on beetles,
worms, slugs, small lizards, birds’
eggs, and chicks.Reticulated
pythonReptiles 436-
South American
green turtleShell is made up of about
60 bony plates that
cover the back and the
underneath of the tortoise
or turtle.TURTLE
Turtles vary greatly in size. The huge leatherback turtle is 4–10 ft
(1.2–3 m) long and weighs up to 2,016 lb (916 kg), while the common
mud turtle is only 3–5 in (7–12 cm) long. Sea turtles, such as the green
turtle shown above, are the fastest swimmers; some can speed along at
almost 20 mph (32 km/h).Most crocodilians, as well as some
turtles, snakes, and lizards, are now
officially protected species.
It is illegal to trade in these
animals and their products.AlligatorSnakes shed their
skin in one piece
when it becomes too
tight, turning it inside
out as they wriggle
out headfirst.Starred
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