Greater stick-nest Rat
Rats belong to the order of Rodentia. The term "rat" does not
describe a group of closely related species, but is a common term for
rodents that look alike to the casual eye, regardless of ancestry:
short-bodied rodents, usually having a pointed muzzle, long slender tail and
dexterous forepaws. Rats include kangaroo rats, Norway rats, cotton rats,
pack rats, wood rats, greater stick-nest rats, roof rats, naked mole rats
and many others.
The term rat usually refers to the
two main species of house rat, the Norway rat and the Roof rat. Both species
originated in Asia, but have spread throughout the world by human travel
overseas. They both belong to the genus Rattus, which includes 51 species.
Rats average life span is 2 to 3 years. They are nocturnal,
have poor eyesight and are
colorblind. They primarily see light, shadow and movement. They do have very
developed senses of hearing, smell, touch and taste. Their hearing is
ultrasonic. Touch is via their long whiskers.
Rats are omnivores. Among other things they eat seeds,
fruit, grains, nuts, flowers, leaves, insects, birds, reptiles, fish, eggs
and fungus. They consume about 1 ounce of food and drink about 1 ounce of
water each day. Their strong teeth are able to gnaw through wood, copper,
cinder block, aluminum, and uncured concrete.
Rats are very social and affectionate animals. They love being in
the company of their own species or humans. They like playing together and
love to sleep curled up together. They take care of the injured and sick
rats in their group. When rats don't have companionship, they can become
lonely, depressed, anxious and stressed. A group of rats is called a
Rats use high-frequency sounds, smell, touch and body
postures to communicate with each other.
Norway rats belong to the species Rattus norvegicus. Other
names for the Norway rat are brown rat, gray rat, common rat, house rat,
wharf rat, barn rat, sewer rat and water rat. They prefer temperate zones.
They burrow extensively in soil and like to nest in basements and lower
portions of buildings. They are poor climbers, but great swimmers.
Norway rats have a heavy and thick body about 7 to 10 inches
long. They weigh about 10 to 17 ounces. Their color may vary from
grayish-brown, a pure gray to a blackish- or reddish-brown. Their underside
is gray to yellow-white. Their nose and muzzle are blunt, their eyes are
small and their ears are close to the body and won't cover the eyes if bent
forward. Their tail is dark on top with a lighter underside and shorter than
their head and body.
The White rat is an albino strain
of the Norway rat, also known as Pink-Eyed White or PEW.
Roof rats belong to the species Rattus rattus. Other names
for the Roof rat are Alexandrian rat, black rat, fruit rat and ship rat.
They prefer tropical and semitropical zones and can be found on all
continents of the earth. They burrow very little and like to nest outside in
trees or in upper portions of buildings. They are great climbers, but don't
like to swim.
Roof rats have a slender body about 6
1/2 to 8 inches long. They weigh about 6 to 12 ounces. Their color varies
from black to brownish-gray. Their underside varies from gray to white.
Their nose and muzzle are pointed, their eyes are large and prominent and
their ears are large and cover the eyes if bent forward. They have a
hairless tail which has a uniform color and is longer than their head and
Female rats average 4 to 6 litters each year. Norway rats
average 8 to 12 pups per litter, Roof rats 4 to 8 pups. Their gestation
period is three weeks and they can become pregnant again within 1 to 2 days
after giving birth, while continuing to nurse their current litter of pups.
The pups are usually weaned when they are about 3 to 4 weeks old. Pups are
born blind and naked. It takes about 7 days for their hair to start growing
and 12-14 days for their eyes to open. The pups stay in the nest built by
their mother until they are weaned. Often litters of numerous females will
share the same nest and are cared for by the all the females, regardless of
who their true mothers are. If a mother dies, the other females will take
over nursing her pups. Male rats don't participate in the parental care.
Rats have a strong social hierarchy. The biggest and
strongest rats will get the best food and harborage.
Rats use their tails to regulate their temperature, to
communicate and for balance. They have glands on the bottom of their feet
and will lie on their backs to sweat. They have no canine teeth, no thumbs,
no gallbladders and no tonsils. They do have bellybuttons.
Rats are intelligent animals. They are more intelligent
than rabbits, hamsters, mice, gerbils and guinea pigs for instance. They
also have excellent memories. Once rats learn a navigation route, they never
Rats are very clean animals. They spend several hours each
day grooming themselves and each other. They are less likely than dogs or
cats to catch and transmit parasites and viruses.
Rats are curious but shy. They prefer to run away rather
than confront a potential threat.
Predators of rats are cats, birds, reptiles and other