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17
Coypu
The coypus (~Myocastor coypus) is an aquatic rodent
native to South America. It has been called the "South
American beaver," but its size is actually closer to
that of a small dog or an agouti. It seems suited to be
a microlivestock species because, compared with most
rodents, it has a large body size and a relatively high
reproduction rate. Moreover, it is easy to manage, and there is much
literature on how to raise it in captivity.2
Fur is the main item of commercial value. In the late 19th century,
it was in such high demand that the animal was nearly exterminated.
However, in 1922 Argentineans began raising coypu in captivity and
this practice spread through South America and to other regions. In
many European countries and in various locations in the United States
some specimens escaped or were released, and coypu have become
established in the waterways.
Coypu meat is tasty and is consumed in many regions of South
America as well as in parts of Europe. Because of the absence of
musk glands, the meat is free of the "gamy" flavor found in squirrels
and rabbits. It is moist, fine "rained, medium light in color, and firm.
It is one of the mildest and tenderest of wild meats.
AREA OF POTENTIAL USE
This animal has been widely distributed, but its area of safest use
is within its natural range in South America.
' These animals are generally called coypu in English, but their fur is known around
the world as nutria. Coypu is the better name to use because throughout South America
the word "nutria" refers to an otter. Other names are swamp beaver and quoulyas.
2 A study in Chile revealed, for example, that 80 commercialized farms were maintaining
48,000 reproducing females and producing 500,000 skins per year. Information from
D.L. Huss.
217
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218
APPEARANCE AND SIZE
MICROLIVESTOCK
The coypu is adapted to a semiaquatic existence and has webbed
feet, valvular nostrils that can be closed to keep water out, and underfur
that remains dry even under water. Its long, powerful claws on the
forefeet are used for grooming, excavating burrows, and digging up
and holding food. The tail is slender; the extremely large incisor teeth
are orange-red.
An adult is 4~65 cm long and weighs 7-10 kg. Some occasionally
weigh up to 17 kg. Males are larger than females. The potage is thick,
with coarse guard hairs overlying the underfur. The soft dense underfur
(the commercially valuable pelt called "nutria") is about 2 cm long on
the belly, and 2-S cm long and less dense on the back. The color is
yellowish to reddish brown on the back and pale yellow on the belly.
DISTRIBUTION
The coypu is distributed through southern Brazil, Paraguay, Uru-
guay, Bolivia, Argentina, and Chile. It has been widely introduced in
North America, Europe, northern Asia, and eastern Africa. As a result
of escapes and releases from fur farms, the animals are now feral in
Europe, North America, northern Asia, Japan, and East Africa. In
the United States, they are abundant in Louisiana, Oregon, Florida,
and the Chesapeake Bay region.
STATUS
In various countries, the animal's status ranges from that of a rarity
to that of a pest. Wild coypu are protected by law in Argentina because
of overhunting, but there are about 100 producers of farmed coypu.3
Elsewhere the animals are destroyed en masse to reduce the threat of
damage to irrigation ditches, dams, and agricultural crops. In England
a decade-long program has eradicated them.
HABITAT AND ENVIRONMENT
Coypu mainly inhabit the banks of fresh or brackish waterways.4
They live in temperate zones and are highly sensitive to freezing
3 Information from D.L. Huss.
4 They look for water for protection and to cool off on hot days. They stay in tall canes
near water during the day and feed on land during the night.
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coypu
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219
The coypu's native distribution. This is the only region safe for raising this extremely
adaptable and potentially pestiferous animal.
conditions. Also, their heat tolerance is poor; lowland tropical regions
may be too hot for them.
BIOLOGY
The coypu feeds mainly at night. The diet consists chiefly of plants,
particularly water plants and reeds. Large amounts of fibrous vegetation
is decomposed in the cecum, where bacteria break down cellulose
particles. Mussels, snails, and other small organisms are also often
eaten.
The animals burrow into soft soil or construct nests out of vegetation
above ground.
Coypu are relatively fast breeding. Females first give birth at ages
ranging from 6 to 15 months. From then on, they produce 2 or 3 litters
a year. They are able to mate and give birth at any time of the year,
although more young are born during certain seasons. The gestation
period is between 128 and 140 days. There are 5 or 6 (sometimes up
to 12) young in each litter. Newborns are well developed, able to see,
and fully covered with hair at birth.
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220
MICROLIVESTOCK
The female's four or five pairs of mammae are located on the side
of the body, an adaptation that permits the young to nurse while
floating with their mothers in the water. In captivity, young are nursed
for two months, but can survive if weaned at five days. The mean
body weight at birth is about 225 g, but growth is rapid during the first
five months.
Coypu have a potential life span of more than six years. However,
they seldom survive more than three years, and in the wild probably
no animals are older than five years.
BEHAVIOR
These are passive creatures, usually entirely lacking in aggression.
They are shy and fearful; the slightest disturbance will send them
scurrying to the shelter of water, a burrow, or other hiding place. With
their large incisors they can bite viciously, but in captivity they tame
down, even to where they can be carried around by hand. Compared
with domestic animals, they are very sanitary in their feeding and
living habits.
In hot climates they are nocturnal, in cooler climates crepuscular,
and in cold weather they become diurnal. Captive animals become
conditioned to diurnal activity if fed during daylight hours. Most of
the active period is spent feeding, grooming, and swimming. Grooming
is done by scratching and "nibbling" the fur, and an oily secretion
from glands located near the mouth and anus lubricates the pelage.
Secretions from the anal glands are also employed for marking out
territory.
Excellent swimmers, coypu spend most of their time in the water.
They can remain submerged for five minutes or more. On land, they
lumber about with awkward, clumsy movements; however, when the
need arises they can run fast and jump short distances.
Although they usually live together in pairs, coypu will form large
colonies. They tend to remain in one area throughout their lives: their
daily "cruising range" has been measured at less than 45 m.s However,
drought or freezing weather can induce mass migrations.
The burrows, which are dug in sloping banks, are usually short with
no branching tunnels and generally end in a simple chamber.
5 W.H. Adams, Jr. 1956. The nutria in coastal Louisiana. Louisiana Academy of Science
19:2~0.
The coypu. Because the guard hairs are coarse, the coypu is a grizzled, unattractive
animal. However, after being dressed, the carcass looks very much like that of a large
rabbit. (John McCusker, The Times-Picayune)
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222
USES
MICROLIVES'rOCK
In South America, the coypu has a long history of use. Nutria fur
was in such high demand and the animal was hunted so avidly at the
beginning of the last century that it became rare and had to be protected
by government decree. As a result, populations increased dramatically.
Nowadays, coypu are protected in many areas, but widespread poach-
ing has reduced their numbers and range.
Many thousands are killed each year just for the guard hairs, which
are used in making felt.
Coypu are used in marsh management to reduce infestations of
aquatic weeds and to keep waterways open.
HUSBANDRY
In most areas where it is found, the coypu is trapped by commercial
hunters. However, as noted, several countries have coypu farms. In
Germany, the animals have been raised on diets consisting chiefly of
potatoes supplemented with oats, clover, corn, hay, green forage,
legumes, turnips, or cabbage. Elsewhere, feeds generally include such
materials as hay, corn, crushed oats, greens, root vegetables, apples,
bread, and rabbit feed.
To confine coypu, a wall of stone or concrete or a fence of stout
wire netting is necessary. It must be set 1 m deep into the ground and
rise 1-1.5 m above ground. Water must be available.
Where selected strains of animals are kept, it is usual to house each
female in separate small compartments, complete with pools and
shelter boxes. Each is then paired with a male, which is removed after
mating to leave the female to rear her brood in seclusion.
ADVANTAGES
The fur is particularly valuable because the female's nipples are so
high that the soft belly fur is unbroken.
This herbivore is much cheaper to feed than the forbearing carnivores
such as mink. Furs of coypu raised in captivity fetch a price about
three times greater than furs from wild animals.6
6 Information from CORFO, Chile.
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coypu
LIMITATIONS
223
Wherever the coypu has escaped it has damaged embankments and
stream banks. The burrows sometimes weaken dikes that protect low-
lying areas from flooding. In northern Europe and eastern England,
for example, it is considered a serious pest. In rice paddies, coypu
could become particularly devastating. They can also damage crops
and natural plant communities.
Coypu can carry viruses that result in toxoplasmosis, papillomatosis,
rabies, and equine encephalomyelitis; bacteria that cause salmonellosis,
paratyphoid, and leptospirosis; protozoans that produce sarcospori-
diosis and coccidiosis; and rickettsia. Common diseases of captive
specimens are bacterial pneumonia, hepatitis-nephritis, Strongyloides
infection, and neoplasms.
European winters often cause the coypu's tail (which is hairless) to
freeze, but the animal hardly seems to notice. A more dangerous
situation arises when lakes, streams, or rivers freeze over; beneath
the ice, coypu cannot find their way as easily as beavers, and often
drown.
RESEARCH AND CONSERVATION NEEDS
Little research needs to be done. There is massive literature on
farming coypu. Nonetheless, the animal's behavior is little studied,
and there are few reliable published observations on its social orga-
nization.
OCR for page 224
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