guinea pig
, (
Cavia porcellus
), a domesticated
species
of South American
rodent
belonging to the
cavy
family (Caviidae). It resembles other cavies in having a
robust
body with short limbs, large head and
eyes
, and short ears. The feet have hairless soles and short sharp
claws
. There are four toes on the forefeet and three on the hind feet. Several breeds of domesticated guinea pigs exist, which are sometimes grouped by coat
texture
and hair length. The term
guinea pig
is also used colloquially to refer to a person who serves as a test subject in an experiment.
Among rodents, domestic guinea pigs are fairly large, weighing 500 to 1,500 grams (roughly 1 to 3 pounds) and having a body 20 to 40 cm (8 to 16 inches) long. The tail is not visible externally. There is a
crest
of longer hairs at the neck, but length and texture of the
fur
vary from smooth (short or long) to coarse and short or long and silky. Coloration is extremely variable: the coat may be white, cream, tan, reddish or chocolate brown, black, or a combined pattern.
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Guinea pigs eat vegetation and do not require
water
to drink if supplied with sufficiently moist
food
, but they must have water if fed dry commercial food. They breed all year in captivity. Females bear up to 13 young per litter (4 is average);
gestation
takes 68 days. Although the young can scamper about and eat solid food the day they are born, they are not fully
weaned
for about three weeks. Females mature in two months, males in three, and captive guinea pigs live up to eight years, although three to five is typical.
No natural population of this species exists in the wild. Guinea pigs were apparently
domesticated
more than 3,000 years ago in
Peru
, coinciding with
humans’
transition from a
nomadic
to an agricultural lifestyle. The
Incas
kept guinea pigs, and the animals were bred during the same period by various people who lived along the
Andes Mountains
from northwestern
Venezuela
to central
Chile
. These rodents remain a sustainable food source for the native peoples of
Ecuador
, Peru, and
Bolivia
, who either keep them in their homes or allow them to scavenge freely both indoors and out. Guinea pigs were taken to
Europe
in the 16th century, and since the 1800s they have been popular as
pets
. They are also used internationally as laboratory animals for studies of
anatomy
,
nutrition
,
genetics
,
toxicology
,
pathology
,
serum
development, and other
research
programs.
The origin of the
colloquial
name
guinea pig
is a subject of much debate. The first part of the name may have been derived from the price of the
animal
in 16th- and 17th-century England?that is, possibly one guinea?or it may have arisen from the animals’ being carried to European markets after first being transferred to ships in ports in
Guinea
. The moniker could also have originated with a mispronounced form of the word
Guiana
, the name of the region where some guinea pigs were collected. Another possible
etymology
is from the name of the class of ships?the Guineamen?that transported the animal. These were vessels that made port in
West Africa
as part of the
transatlantic slave trade
. The second part of the name also originated with Europeans, who compared the squealing sound the animal made (as well as the taste of its cooked flesh) to that of a
pig
.
There are five nondomesticated members of the genus
Cavia
that are also called guinea pigs: the
Brazilian guinea pig (
C. aperea
) found from
Colombia
, Venezuela, and
the Guianas
south to northern Argentina; the
shiny guinea pig (
C. fulgida
), inhabiting eastern Brazil; the
montane guinea pig (
C. tschudii
), ranging from Peru to northern Chile and northwestern
Argentina
; the
greater guinea pig (
C. magna
), occurring in southeastern Brazil and Uruguay; and the
Moleques do Sul guinea pig (
C. intermedia
), which is limited to an island in the Moleques do Sul
archipelago
off the southern coast of Brazil. Breeding and molecular studies suggest that the domestic guinea pig was derived from one of the wild Brazilian, shiny, or montane species.
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