WEBVTT

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The roof rat is a climbing animal,
as the name implies.

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The roof rat prefers to live above ground

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and frequently nests
under the eaves of roofs.

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Like the Norway rat,

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the roof rat generally
uses established runways

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in getting to and from its harborage.

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The runways of the roof
rat are usually above ground.

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This is a typical roof rat run.

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It can be identified by the greasy
semicircular smudges

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left by the rat's body
where it contacts the beams.

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To the roof rat, a runway is a safe path
followed by other rats before.

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Using such a runway gives
a rat a sense of security.

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The rat knows at one end must be harborage

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and at the other end, food or water.

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The runway often leads
through double walls.

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The rat's vibrissae,
or whiskers, and its long,

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tactile hairs enable it to move
safely through narrow places.

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The rat knows that the runway leads

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to an established source of food supply,

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as shown by its unhesitating
and direct approach to the food.

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The roof rat is a pantry thief
and is fond of cereals and grains.

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It is not primarily a garbage
feeder but will eat garbage

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when other food is not available.

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A rat must have access
to a source of water.

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The need for water
is conveniently fulfilled

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when dishes are left
soaking overnight in the sink.

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The roof rat is peculiarly
adapted to climbing.

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It has sensitive finger-like toes,
ending in talon-like nails.

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The front paw has four claws
and a rudimentary thumb.

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The inside of the paw is padded.

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The hind paw has five toes.

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Equipped with these tools,

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the roof rat can easily climb
a three-quarter-inch pipe.

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Notice the way the rear and front
paws are held in the descent.

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The Norway rat can climb too,
but not nearly as well as the roof rat.

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The roof rat can crawl up
a three-inch pipe with ease.

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The rough finish of the metal
helps it to take hold with its claws.

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The Norway rat, by trial and error,

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learns to brace its back
against the wall and make the climb.

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A roof rat bracing its back

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against the wall
can climb a four-inch pipe.

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Without the wall,
even a roof rat would be unable

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to climb a pipe four inches in diameter.

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A brick wall can be scaled
by a roof rat if the edges

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of the brick protrude
even one-sixteenth of an inch.

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The Norway rat can pull
itself up the same wall,

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but with a little more difficulty.

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A roof rat
has an excellent sense of balance

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and can walk on a wire with skill.

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The Norway rat is more awkward

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and falls off before learning
to balance itself.

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A roof rat can race surefootedly
along a smooth, narrow pipe.

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The Norway rat falls off.

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The superior climbing
ability of the roof rat explains

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its preference for nests in places
like the air-vent shaft on a roof.

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The wire mesh screen in the shaft
supports the roof rat's nest.

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The dead space between the roof
and parapet wall provides harborage.

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From here,
the rat has access to the interior

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of the building by way
of the soil vent pipe.

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In the South and Southwest United States,

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the roof rat frequently nests in palm

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or other trees that provide
shelter in a mild climate.

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They subsist partially on the fruit
of the tree in which they nest.

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At night, by such means as service wires,
they gain access to homes.

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Once in the building,

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the rat picks up established
trailways leading to food.

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The roof rat, like the Norway,
lives its entire life close to man,

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yet in concealment from him.

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In these remarkable photographs,

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actual scenes of the birth
of a roof rat litter are shown.

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The mother rat, with its forepaws
and teeth, helps deliver its young.

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The rat washes its newborn with
its tongue and eats the placenta.

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The rat places the newborn out of the way

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and concentrates
on each infant as it is born.

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It cuts the cord and consumes it.

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In this manner,
the roof rat delivers its entire litter.

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The baby rats are blind and helpless.

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The mother rat almost immediately
begins to suckle it's young.

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As in the case of the Norway,

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the young roof rats are suckled
for four or five weeks.

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By that time, they are weaned
and begin to explore their environment.

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With growing independence,
they widen their range of activity.

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With an increased population,
and when food

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or harborage is scarce,
vicious fighting results.

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Though the living habits
of Norway and roof rats differ,

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there is a basic similarity
in their life patterns.

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Both are fundamentally spoilers,

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living on man's property
and eating his food.

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Both have physical
characteristics that equip them

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to live undercover as parasites of man.

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Both depend on their senses,
particularly those of touch and smell,

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to move around freely in the dark.

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Both build their nests
in concealed places.

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Both use established runways
linking food and harborage.

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Although their food preferences differ,

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both can eat anything
that man eats or discards.

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Sometimes, there is competition
between the species for the same food.

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In such a case, vicious fighting results.

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The roof rat depends on speed
and agility to escape the Norway rat,

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but the Norway rat, which is stronger
and more ferocious, wins.

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Wherever Norway rats invade a roof
rat area, the roof rats tend to leave.

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Both Norway and roof rats
have many natural enemies.

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Among these are owls, hawks, and snakes.

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In rural areas, rat snakes will hide
in barns and fields, near rat runs,

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and stalk the rats.

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As the rat goes by,
the snake makes a pass at the rat.

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The rat may defend itself
or carry the battle to the snake

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but once the snake has thrown a coil
around the rat, the rat cannot escape.

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The snake will crush
it and consume it later.

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In spite of the rat's natural enemies,
it has survived and prospered.

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Whichever route it is, Norway or roof rat,

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it is a tenacious and adaptable animal.

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To meet the threat it poses
man must use his knowledge

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and all the scientific resources
at his command.

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