Is A Reptile...
Reptilia has over 6500
species in 48 families and 905 genera
or turtles & tortoises 244 species in 13 families and 75
or Tuatara has 1 specie.
crocodiles and alligators has 22 species in 3 families and 8 genera.
Squamata or snakes,
lizards, and worm lizards.
This list is subject to change at the whims of new science***
Serpentes or snakes
has 2389 species in 11 families and 417 genera.
Snakes have generally
between 200 and 400 vertebrae. Each is connected by at least articulated
surfaces which give it that smooth and supple movement when combined
with a set of interlocking muscles. The skull is very flexible and
the bones of the upper and lower jaws are attached only with ligaments
and muscle tissues and thus can be moved in just about any direction.
Teeth are in reality simply inward curved sharp spikes designed
to first impale, then hold, and finally to help move the prey back
down the esophagus. Other adaptations is that snakes have evolved
away from the pectoral girdle and sternum found in most animals
with front limbs. This allows them to swallow larger prey.
It was originally thought that snakes "walked"
on their ribs much like a millipede. However, what really happens
is that they use their large ventral scutes (scales) which are found
on their abdomens or bellies. These scutes are attached to the ribs
with muscles and by simply moving them back and forth or pulling
a snake can move in a fairly straight line. This is called the "rectilinear
method" In addition snakes can "swim" either in the
water or on the land. This is called the "lateral undulatory
method" and is composed of a series of s curves. Where the
curves hit the ground they "push off" and gain speed.
Related to this is the "side winding method" used by a
few snakes such as the desert dwelling American sidewinder. In this
case the head is thrown in an arch forward while the body uses the
LU method behind it. This allows much of the body to be off the
often hot surface while still moving in a forward direction. The
fourth style of locomotion is used by some species of tree snakes.
It is called the "concertina method" and is somewhat like
and inch worm's method. The prehensile tail tightly grips the tree
and then the head quests upward until it has a firm grip or drape
over another part of the tree. Then the tail is pulled up until
it has another grip just below the head and the process continues
to repeat itself as the snake progresses up the tree or bush.
All known snakes reproduce sexually with the male having
two hemipenes which are inserted one at a time into the females
cloaca to fertilize the eggs internally. Most snakes lay eggs but
many species do have live young. Most eggs are laid in a crude nest
of some kind and then leave but a few actually receive parental
protection. Pythons are noted for coiling around their eggs and
by bodily contractions actually keep the eggs warmer than the surrounding
temperature. King Cobras are very protective of their nesting area
and will attempt to chase anything that wanders too near away.
All snakes have some sort of vision, even the "blind snakes."
Some only distinguish light and dark while others see only motion.
A few like some of the tree snakes have vertically elliptical pupils
that allow them to see when it is very dark while the day version
of the same actually are thought to see quite well. No snake has
any eyelids or eyelashes but instead rely on a transparent covering
called the brille. Each time they shed they get a brand new brille
and so even scratched or damaged eyes are often renewed in this
Snakes were likely to have developed under the ground and
thus had very little need for acute hearing. The ear is basically
internal and connected to the lower jaw. What they "hear"
is in the range of low frequency sounds vibrated through the ground.
Even the rattlesnake can not hear his own high pitched rattle.
Where snakes really excel is in their ability to explore their surroundings
with taste. Snakes mostly explore their environment "chemically."
The tongue waving in and out of the mouth is actually picking up
molecules of "scent." These molecules are then inserted
in their equivalent of a microprocessor called the "Jacobsons
organs on the inside of the mouth. This allows a snake to make minute
detection's about prey or enemies or even allow them to find mates
far, far away.
Sensing: Many of the Boas, pythons, and venomous snakes
posses the ability to sense infrared heat coming from all living
beings. The pits on the side of rattlesnakes head allows him to
sense the difference between a mouse hiding behind a cactus. Or
a green tree python to find a bird sleeping silently above him in
a tree. Some snakes have such sensitive apparatus that they can
detect differences down to .002 degrees Fahrenheit.
or lizards have 3751 species in 16 families and 383 genera.
The skull of lizards is quite different from those of snakes. However,
we believe that snakes did evolve from lizards so there are some similarities
as well. Chief among them is the fact that the bones of their skulls
are only loosely attached to one another. The lower jaw is composed
of two halves and are united at the front. This tends to restrict
the size of the meal that can be swallowed. At the back of the oral
cavity the tongue is attached.
called pleurodont meaning that the teeth are weakly attached to
the inside of their jaws but not into the jaws themselves. The few
exceptions to this are the group of acrodonts which are teeth attached
somewhere on the jaw. The rest of the skeleton on lizards are variable
and very unlike snakes primarily in that they have four functional
skin of lizards are generally a hard horny substance that is folded
together to make various types of scales. They can be small or large
and all touch one another called "juxtaposed", are smooth
with ridges called "keeled", or overlap and are called
"imbricate." Scales have many purposes. Sometimes they
are used as a way to absorb solar energy and warm up quicker. Other
times they are used as armor or sexual display with many a bizarre
crest or spines. And of course they differ from amphibians in that
the scales prevent water loss.
Lizards as a species have explored it all. The typical lizard has
four appendages with 5 toes on each. They may be barrel shaped,
pipe shaped, flattened or you name it. In addition we have several
species of lizards who have no limbs whatsoever and undulate side
to side like primitive snakes. Still others have only vestigial
legs front, back, or both. And then you have the many adaptations
found throughout. Examples are the webbed feet of the Marine Iguana,
Basilisks which can run on water, and Gecko feet that can climb
up the smoothest glass. We even have prehensile tails that allow
hanging from tree branches like Crocodile monitors. And perhaps
the most unusual of all is the Flying Dragon from Asia that have
the ability to glide just like flying squirrels. This group of reptiles
is just plain versatile in ways to get around.
see versatility. Most species use internal fertilization, but we
also have unisex cloning such as Whiptails, Racerunners, and some
other desert lizards. In addition their have been confirmed reports
from some types of Chameleons, Geckos, Night Lizards, and Chisel-Teeth.
The mechanism by which this happens is not completely understood
nor the reason why it happens, but it is called "parthenogenesis."
An external ear opening is present in most lizards and they likely
hear much the same as other eared reptiles.
adaptations of the many species of lizards is legendary. There are
undoubtedly many, many we will never even know about as the lizards
of smaller size do not fossilize well. But just looking around at
the thousands of existing species gives a clue to the great diversity
there was and still is. The very long and sticky tongues of the
true chameleons which can snare prey more than a body length away
are a good example. The ability to reproduce without males is another.
Did some of the dinosaurs also employ this method"? It is not
all that unlikely. Having an expendable tail, large colored tongue
for defense, color changing for protection, large expandable frills,
playing dead, and 360 degree independent eye movement are some of
the other successful adaptation lizards are capable of
and Feeding: Lizards and their ancestors
have been around for a very long time. The reason appears to be
because of their adaptiveness. The first species to adapt to land
in the earth's early history was the insects. And where plentiful
prey is available the predators are soon to follow. Lizards started
off eating insects and never had a real reason o change. True, there
are some herbivores among the many lizard species, but it is in