The Anatomy Section
In this section, I will give you the names of the snake's body parts and tell you what they do.
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Choose which part of the body which you would like to find information about: |
A snake's skull is suited to their specialized feeding habits. Since snakes
do not have any chewing teeth and are also limbless, all food must be swallowed
whole.
If you have seen a snake eat, you will see that the mouth opens very wide to
be able to swallow its prey. It would equal to us eating a whole basketball! For
the snake to be able to do this the bones on the snakes skull are very loosely
connected by flexible ligaments. The jaw can be dislocated, separating from the
skull to produce an enormous gape, and the two halves of the jawbone can also be
spread widely apart at the chin. Usually after the snake has finished eating,
you will see it yawn. This is how the snake puts its jawbones back in place.
Snakes have many more teeth found in mammals. Many snake species have over
200 teeth, which can be found in two rows along the top and bottom of its mouth.
Unlike mammals, the teeth are attached to the side of the jawbone. Snakes cannot
use their teeth to chew pray since they are all pointing backwards. This is to
help the snake swallow and hold it's prey. If one of it's teeth comes out or
gets broken it is quickly replaced by another tooth (this is much like sharks
teeth). Also snakes usually shed their teeth to always make sure that they are
sharp. All of the snake's teeth are the same length and size except the
elongated teeth of Boas and Pythons and the Venomous snakes.
Snakes eyes differ from eyes of mammals or other vertebrates. Other
vertebrates are able to focus a sharp image on he retina of their eyes, by using
a special muscle to change the shape of the lens. In many snakes though these
muscles are absent, therefore a snake cannot focus on a stationary object. They
are however very sensitive to movement.
As we already know that snakes cannot see very well, so how do they know
what's going on around them. They have got a special organ (obviously discovered
by Jacobson?) in the top of their mouth. If you watch a snake you will see its
tongue shooting in and out of its mouth. The tongue picks up micro-particles
found in the air, gets sent to the Jacobson's Organ (the organ has a direct link
to the brain) and then goes to the brain, which deciphers it.
The snake's brain (in structure) is very similar to a bird's brain but the
snakes lacks the enlarged cerebral hemispheres found in birds and mammals. The
cerebral is the part of the brain, which contains the learning. Sine the absence
of the cerebral hemispheres, it is correct to say that snakes aren't very
intelligent. But they can learn a fair amount. Some snakes have learnt when
their feeding times are and often the owner will find them waiting.
The lungs of a snake must fit inside a long cylindrical body; their structure
is somewhat different from those of most animals. In most snakes the right lungs
is usually the largest and extends for over a 1/3 of the body. The left lung is
then VERY small or absent. In effect, snakes only have one lung. During
feeding, when the mouth may be blocked with food for up to an hour, the snake is
able to breathe by extending a muscular extension of its windpipe, called the
epiglottis, from the bottom of the mouth. It protrudes from underneath the prey
to reach air and allow the snake to breathe.
Most reptiles (except the crocodilians), snakes have a very primitive
three-chambered heart that is not as effective as the four-chambered hearts
found in mammals. In snakes the blood is pumped into one top chamber (oxygen
depleted) then the oxygen rich blood from the lungs gets pumped into the other
top chamber. They all get empties into the lower one and then circulated
throughout the body. Because of this inefficient method of distributing oxygen,
even the most active snakes tire easily and have to rest for a period of time.
The snake's stomach is very strong and elastic, and can expand enormously to
obtain the large prey animals eaten by snakes. The digestive juices are powerful
so nearly all of the prey is digested which includes most of the bones and
teeth. Since snakes digest their "whole prey", they can go for a long
period of time without having to eat.
Snakes have very large kidneys in proportion to their body size. These are
found in the abdominal regions, the left kidney behind the right. The Kidneys
(like in mammals) filter waste products from the bloodstream and pass them on to
the cloaca (unlike in humans) for elimination. Mammals, which excrete nitrogen
wastes in the form of water-soluble urea, snakes excrete these body wastes as
crystals or uric acid, which form a dry white paste and are expelled along with
the feces. This process allows snakes to be extremely efficient in their use of
water.
Unlike mammals, snakes do not have separate urinary, reproductive and anal
openings. Instead the urinary, digestive and reproductive tracts all empty into
a common chamber, the Cloaca. All of the waste material is stored here until it
can be eliminated. The cloaca opens to the outside through a transverse sit just
behind the snakes tail.
Some snakes also have special glands, which also empty into the cloaca. These
glands contain a foul-smelling musk, which can be ejected when the snake is
frightened or threatened.
Like mammals, snakes practice in internal fertilization in which the male sperm is introduced directly into the female's reproductive organ, the cloaca. Instead of a penis the male has a pair or copulatory organs called hemipenes. During mating only one pair of hemipenes is actually used. The other is used as a backup!
If I have left anything out or you want some
more information e-mail me at dylanvdm@icon.co.za
