Snakes do not have
especially keen senses of sight or hearing. They
rely instead on special sense organs to provide
them with information about their environment.
Snakes have an eye on each side
of the head, giving them a wide field of view,
but they cannot focus them well and have sharp
vision for only a short distance.
Snakes lack outer ears and
eardrums, but they do have inner ears and can
hear a limited range of sounds carried in the
air. Certain bones in a snake's head respond to
sound waves and transmit them to the inner ear.
A snake's tongue has few taste buds. It
is used with an organ of smell called the Jacobson's
organ, which, along with the nostrils,
provides snakes with a keen sense of smell. The
Jacobson's organ consists of two hollow sacs in
the roof of a snake's mouth, each of which has
many nerve endings that are extremely sensitive
to odors. A snake sticks out its tongue to pick
up scent particles in the air or on the ground or
some other surface. When the snake pulls its
tongue back into the mouth, theseparticles enter
the Jacobson's organ. The organ enables a snake
to follow the scent trail of its prey.
Certain snakes also have
special heat-sensitive pit organs. Pit
vipers have two pit organs, one on each side of
the head between the eye and nostril. Some boas
and pythons have many pits along the lip of the
upper jaw. Pit organs enable a snake to detect
the exact location of another animal by the body
heat it gives off. As the snake moves its head
from side to side, the pit organs detect changes
in the air temperature. The snake can then
accurately direct its strike, even in the dark. A
snake with pit organs can sense a change in
temperature near its head of less than 1° F.
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