1. I CAN Explain the differences
between Reptiles and
Amphibians.
A Presentation From:
Living Desert Zoo and Gardens State Park
Carlsbad, New Mexico

2. Reptiles

3. There are 6,800 reptile species on earth.
The major reptile groups are:
• Alligators and Crocodiles
• Turtles and Tortoises
• Snakes
• Lizards

4. Reptiles are Vertebrates
They have an internal skeleton with a backbone.

5. Reptiles Have
Dry, Scaly Skin
Reptiles have tough, dry, scaly skin made of keratin (what fingernails are
made of) that protects them from drying out. The large scales of turtles,
tortoises, and crocodilians are called scutes.

6. Reptiles shed their skin to grow bigger.
Snakes shed their skin all in one piece, turning it inside out as
they shed. The skin is left in one piece and looks like a tube.
An adult snake will shed two to five times a year. A young
snake will shed more often as it grows faster.
Corn Snake
shedding its skin
Most lizards shed their skin in pieces. That often begins with
the skin splitting down the lizard’s back. A rapidly growing
lizard might shed every two weeks. Legless lizards shed their
skins like a snake.
Green Anole
lizard eating its Leopard Gecko
shed skin shedding its skin

7. Crocodiles and alligators have large scales (scutes), which
are shed individually .
Scutes on a live Alligator
Alligator
Scute Fossils
A turtle’s skin is shed like a lizard’s. The hard shells of
most turtles are not shed. Instead new layers are added to
the underside of their shells. The age of the turtle can be
determined by the number of rings on its shell’s scutes.
Turtle Scutes

8. Reptiles are Ectothermic
Most reptiles are ectothermic - they use their environment to warm and cool
their bodies. If they are cold, they must lay in the sun to raise their body
temperature. If they get too hot, they must find shade to cool off. Many
reptiles are active at night, so they can avoid becoming too hot and having
their skin dry out.

9. Snake
Lizard in egg Turtle
Reptiles Lay Eggs
Reptiles produce tough, leathery shelled eggs that keep moisture and
warmth in and predators out. Most reptiles lay their eggs in a place
where they will be kept warm and humid. Some reptiles keep their
eggs inside their bodies and then give birth to live young. Most reptiles
lay their eggs and then leave them.

10. Reptile Babies Look Like Little Adults
Reptiles possess most of their adult characteristics at the time
of hatching. Unlike most amphibians, they do not undergo a
larval stage or experience metamorphosis.

11. Is it an Alligator or a Crocodile?
American Alligator American Crocodile
•8 to 13 feet long •13 to 16 feet long
•800 to 1,000 pounds (males) •800 to 1,100 pounds (males)
•70 to 80 teeth •60 to 66 teeth
•Broad, U-shaped snouts •Long, slender V-shaped snouts
•Bottom teeth are not visible when •Lower teeth are visible when the
the mouth is closed mouth is closed
•Brown, gray, or nearly black •Dull grayish-green or olive-green color
•Life span: 30 to 35 years •Life span: 60 to 70 years
•Live mostly in fresh water swamps •Live in brackish and saltwater wetlands
•Mothers assist babies in hatching. •Mothers assist babies in hatching. Young are
Young stay with mother for a few ready to be on their own right away.
months.

12. Lizards
There are over 4,675 lizards species in six families:
Geckos Iguanas
Monitors Chameleons
Gila Monsters Skinks

13. Lizards
Lizards have different types of diets. Some eat only
plants (herbivores), some eat only insects or small
mammals (carnivore), and some eat both plants and
animals (omnivores).
Some lizards (such as whiptails) lose their tails when
they feel threatened. The lost tail distracts the
predator so the lizard can get away. The tail grows
back later.
Some lizards (Gila monsters) store food
in their fat tails.
Some lizards (geckoes) have special feet which allow
them to hold on to walls, ceilings, etc.

14. Snakes
• There are about 2,600 species of snakes.
• Most snakes are not venomous.
Northern Water Snake
• All snakes can bite, swim, climb,
• and drink water.
• Snakes only strike people in self-defense.
• Most baby snakes are able to care for
themselves from the time they are born.
• All snakes are carnivores (meat eaters).
• Their hundreds of tiny vertebrae and ribs
allow them to be very flexible.

15. Tortoises
Turtles •are turtles that live on hot dry land, and
•spend most of their lives in water. go to water only to drink or bathe.
•have low domed shells. •mostly have high domed shells.
•have webbing between their •have elephant shaped legs.
toes for swimming. •have round stumpy feet for walking and
•can be carnivores (meat), digging burrows.
herbivores (plants), or omnivores •eat low growing shrubs, grasses,
(both.) and cacti.
•do not have teeth, but they have as •do not have teeth, but they do have a sharp
beak.
sharp beak.

16. Amphibians

17. There are about 4,000 species of amphibians.
The major amphibian groups are:
1. Frogs and Toads
2. Salamanders
3. Caecilians (she-SILL-yens)
(a legless, salamander-type animal)

18. Amphibians are Vertebrates
They have an internal skeleton and a backbone.
Bull Frog Skeleton Toad Skeleton

19. Amphibians are
Ectothermic
Amphibians are ectothermic - they use their environment to warm and
cool their bodies. If they are cold, they must lay in the sun to raise their
body temperature. If they get too hot, they must find shade to cool off.
Many amphibians are active at night, so they can avoid becoming too
hot and having their skin dry out.
Couch’s Spadefoot Toad Green Frog
Tiger
Salamander

20. Amphibians Have Special Skin
Amphibians have thin, permeable skin. This means the skin lets water pass
into their bodies easily. Many amphibians don’t need to drink water.
Animals that don’t live near the water absorb enough water from the moist
soil they live in. Their thin skin also allows them to absorb oxygen. This is
helpful for the animal because they have small lungs.
Bull Frog Tiger Salamander

21. Amphibians Shed their Skin
• Frogs, toads, and salamanders have thin skins that
they shed regularly.
• They shed their skin in one piece.
• Once the skin is shed, they eat it!

22. Amphibians Lay Their Eggs in
Water
Amphibian eggs don’t have shells. Instead they are protected by a clear,
jellylike substance and must be kept it water or in wet conditions.

23. Amphibians Go Through Metamorphosis
Young amphibians do not look like they will when they are adults.
Amphibian means "double life" in Greek. Most amphibians start life
in the water and then, through metamorphosis, develop into adults
that live mostly on land.
During metamorphosis the animals’ bodies will have many changes.

24. Metamorphosis of a Frog
Adult frogs with spawn (jellylike eggs) Embryos beginning to split in two
Tadpoles still in spawn
The younger
tadpoles still have
their gills. The older
tadpoles have lost
their gills and are
breathing with
lungs.

25. The back legs have grown a little.
The back legs are just
starting to develop.
The back legs are developed.
This froglet is now
8 weeks old. It still
has its tail, but it
looks almost like an
adult.
The front legs are now present.

26. Salamander Metamorphosis
Salamanders in eggs.
Salamander with gills.
Their heads are not as Salamander with gills.
large as a frog tadpole. The front legs develop first.
This adult salamander is
now able to live on the
land. Salamanders like to
stay under moist leaves and
rocks.

27. Frogs and Toads
•Frogs have ridges along the sides of their •Toads have plump bodies with large glands on the sides of
backs, narrower bodies and faces and large
eardrums. their faces.
•They have moist, smooth skin. •They have dry, warty (bumpy) skin.
• Frogs have teeth. •Toads do not have teeth.
•They have long, powerful legs. Most frogs
have webbed hind feet and pointed toes. •They have plump, shorter, less powerful legs (for walking).
•They lay their eggs in clusters of single eggs. •They lay their eggs in long chains. A few toads give birth
•They live mostly in water. to live young.
•Their tongues are attached in the front of •They live on land as adults. Toads return to the water to lay
their mouths, so they can reach far to catch eggs.
prey.
•They jump long distances to get away from • Their tongues are attached at the back of the mouth.
predators.
•Toads have stronger poison glands for protection. In some
•Most have mild poison glands, which don’t species, the poison is strong enough to kill dogs and cats.
protect them much from predators.

28. Prehistoric Reptiles and Amphibians
Many prehistoric reptiles and amphibians became extinct thousands of
years ago. By looking at the skeletons (fossils) of these animals, we have
a good idea what they looked like. Many of today’s reptiles and
amphibians look much like the prehistoric ones, but usually a lot
smaller.
Challenge: Use the prehistoric animal’s skeleton to determine what
kind of animal it was. Answers are on the next slide.
? ? ?
? ?
? ?

29. What were they?
Alligators?
Frogs?
Lizards?
Salamanders?
Snakes?
Turtles?

30. Prehistoric
This alligator lived in
Colorado about
50 million years ago.
Today
This alligator from Florida
grew to be about 20 ft. in length.
Today, the American Alligator
grows to be 8 to 13 ft. long and
weighs just over 1,000 pounds.

31. What was it?
Alligator?
Frog?
Lizard?
Salamander?
Snake?
Turtle?

32. Prehistoric Today
This sand monitor from
Australia weighs 13 lbs.
and is 4.6 ft. long.
This 80 million year old lizard
fossil is from the Gobi Desert.
This whiptail lizard lives in the
Chihuahuan Desert and its body is
2 ½ - 4 in. long.

33. What was it?
Alligator?
Frog?
Lizard?
Salamander?
Snake?
Turtle?

34. Prehistoric
Today
This frog from Germany
is 49 million years old.

35. What were they?
Alligators?
Frogs?
Lizards?
Salamanders?
Snakes?
Turtles?

36. Prehistori Today
c
This Pachyrhachis problematicus was
found in Israel.
This boa constructor from
Columbia is 13 ft. long and
weighs 60 lbs.
This Titanoboa cerrejonesis was found
in Columbia. Scientist believe it weighed
1,140 lbs. and was 42.7 ft. long.

37. What was it?
Alligator?
Frog?
Lizard?
Salamander?
Snake?
Turtle?

38. Prehistoric
Today
This prehistoric salamander from Tiger Salamander
Germany is almost 6 feet long and Today salamanders have
lived nearly 280 million years ago. bodies that are
from 4 to 8 inches long.

39. What were they?
Alligators?
Frogs?
Lizards?
Salamander?
Snakes?
Turtles?

40. Prehistoric
This turtle from Kansas is over 65
The Meiolania was an 8.2 ft. long million years old.
tortoise found in Australia. Its head
was 2 ft. wide, which prevented it Today
from being able to pull its head This alligator snapping turtle is one of
completely into its shell. the largest freshwater turtles in the
world. It can weigh up to 200 pounds.
The Proganochelys quenstedtii was a
3.3 ft. long turtle found in Germany.
It had a long tail with spikes that it
used as a club.