Reptiles and Amphibians

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Reptiles and Amphibians
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Reptiles
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(No Transcript)
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Reptiles are Vertebrates
They have an internal skeleton with a
backbone.
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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.
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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. Most lizards shed their skin in
pieces. That often begins with the skin
splitting down the lizards back. A rapidly
growing lizard might shed every two weeks.
Legless lizards shed their skins like a
snake.
Corn Snake shedding its skin
Green Anole lizard eating its shed skin
Leopard Gecko shedding its skin
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Crocodiles and alligators have large scales
(scutes), which are shed individually . A
turtles skin is shed like a lizards. 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 shells scutes.
Scutes on a live Alligator
Alligator
Scute Fossils
Turtle Scutes
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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.
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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.
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Is it an Alligator or a Crocodile?

• American Crocodile
• 13 to 16 feet long
• 800 to 1,100 pounds (males)
• 60 to 66 teeth
• Long, slender V-shaped snouts
• Lower teeth are visible when the
• mouth is closed
• Dull grayish-green or olive-green color
• Life span 60 to 70 years
• Live in brackish and saltwater wetlands
• Mothers assist babies in hatching. Young are
• ready to be on their own right away.

• American Alligator
• 8 to 13 feet long
• 800 to 1,000 pounds (males)
• 70 to 80 teeth
• Broad, U-shaped snouts
• Bottom teeth are not visible when the mouth is
  closed
• Brown, gray, or nearly black
• Life span 30 to 35 years
• Live mostly in fresh water swamps
• Mothers assist babies in hatching. Young stay
  with mother for a few months.

  
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Lizards
There are over 4,675 lizards species in
six families
Geckos
Iguanas
Chameleons
Monitors
Skinks
Gila Monsters
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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.
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• 
  Snakes
• There are about 2,600 species of snakes.
• Most snakes are not venomous.
• 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.

Northern Water Snake
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• Tortoises
• are turtles that live on hot dry land, and
• go to water only to drink or bathe.
• mostly have high domed shells.
• have elephant shaped legs.
• have round stumpy feet for walking and digging
  burrows.
• eat low growing shrubs, grasses,
• and cacti.
• do not have teeth, but they do have a sharp beak.

• Turtles
• spend most of their lives in water.
• have low domed shells.
• have webbing between their
• toes for swimming.
• can be carnivores (meat), herbivores (plants), or
  omnivores (both.)
• do not have teeth, but they have as sharp beak.

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Amphibians
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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)
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Amphibians are Vertebrates
They have an internal skeleton and a backbone.
Toad Skeleton
Bull Frog Skeleton
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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.
Couchs Spadefoot Toad
Green Frog
Tiger Salamander
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Amphibians Have Special Skin
Amphibians have thin, permeable skin. This means
the skin lets water pass into their bodies
easily. Many amphibians dont need to drink
water. Animals that dont 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.
Tiger Salamander
Bull Frog
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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!

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Amphibians Lay Their Eggs in Water
Amphibian eggs dont have shells. Instead they
are protected by a clear, jellylike substance
and must be kept it water or in wet conditions.
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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.
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Metamorphosis of a Frog
Embryos beginning to split in two
Adult frogs with spawn (jellylike eggs)
Tadpoles still in
spawn
The younger tadpoles still have their gills. The
older tadpoles have lost their gills and are
breathing with lungs.
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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.
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Salamander Metamorphosis
Salamanders in eggs.
Salamander with gills. Their heads are not as
large as a frog tadpole.
Salamander with gills. 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.
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Frogs and Toads

• Frogs have ridges along the sides of their
  backs, narrower bodies and faces and large
  eardrums.
• They have moist, smooth skin.
• Frogs have teeth.
• They have long, powerful legs. Most frogs have
  webbed hind feet and pointed toes.
• They lay their eggs in clusters of single eggs.
• They live mostly in water.
• Their tongues are attached in the front of their
  mouths, so they can reach far to catch prey.
• They jump long distances to get away from
  predators.
• Most have mild poison glands, which dont protect
  them much from predators.

• Toads have plump bodies with large glands on the
  sides of their faces.
• They have dry, warty (bumpy) skin.
• Toads do not have teeth.
• They have plump, shorter, less powerful legs (for
  walking).
• They lay their eggs in long chains. A few toads
  give birth to live young.
• They live on land as adults. Toads return to the
  water to lay eggs.
• Their tongues are attached at the back of the
  mouth.
• Toads have stronger poison glands for protection.
  In some species, the poison is strong enough to
  kill dogs and cats.