The most domesticated rat is the Black Rat (rattus
Probably the most abundant and certainly the most
domesticated of the fifty-six or so rodent species of Rattus
is the Black Rat, scientifically and redundantly named
Rattus rattus, and also known as Roof Rat, House Rat, Asian
Black Rat, and Ship Rat.
Although it is called the Black Rat, rattus rattus can
actually be found in many color variations including brown,
although it is in a different subfamily than the true Brown
Rat. Most wild Black Rats are black on top with a lighter
colored belly. Domesticated Rattus rattus comes in a wide
variety of colors and combinations of colors of white,
black, agouti, and grey. This species in not as commonly
bred in captivity as the Brown Rat that was the ancestor of
most of today's pet "Fancy Rats," but it does make a good
pet rat and is the preferred species by some rat keepers.
House Rats are medium-sized rats. Their ears are fairly
large, and their tails are usually longer than their six to
nine inches (sixteen to twenty-two centimeters) heads and
bodies. The tail is often used like an acrobat's balancing
beam as the rat climbs or walks narrow walls, wires or the
ropes and chains of ships. Male rats are heavier and longer
than females, sometimes weighing in at as much as ten or
eleven ounces (three hundred grams.)
Ship Rats are believed to have originated in India or
nearby, but due to their habit of traveling in human
baggage, especially on large ships, they are now found on
every continent, especially in the seacoast cities.
Rattus rattus used to be the primary species that was found
living with humans in general, and they are still the most
common in tropical regions of the earth, but in colder
climate they are outnumbered by their close relatives the
Norway Rats who are more aggressive and also breed better
than the Black Rat in colder areas.
Roof Rats are opportunistic and omnivorous eaters like most
rats, but they are primarily vegetarian, eating fruit,
grains and other vegetation. They are poorer swimmers but
better climbers than the Brown Rat common to Asian cities,
and Black Rats are seldom found in the sewers or ditches
where other species make their home. Rather, this species
often lives in high places such as the upper floors of city
buildings or the branches of trees in forested areas.
This species in the wild is primarily nocturnal, and spends
at least the middle of the day resting in its nest made from
twigs and leaves or whatever manmade items seem suitable to
the rat, such as pieces of upholstery, discarded clothing,
cardboard, and the like. Sometimes the nest is hidden in a
burrow or the walls of a building. The territory of a Rattus
rattus is usually not larger than one hundred square meters,
and these rats usually live in colonies or family groups
within their feeding territories.
In the wild, Rattus rattus is often a damager of crops and a
carrier of disease, including having been primarily
responsible for the spread of the Bubonic Plague epidemic in
the Dark Ages. But in captivity this species has done great
good for man as a subject of medical experiments and has
brought great joy to many people as a friendly, charming,
and intelligent pet.