Nutria Rat
Also known as…
• Scientific name: Myocastor coypus
Molina
• Common names: Nutria, coypu, coypu
rat, nutria rat, swamp beaver
Introduction
• The Nutria Rat was native to South
America, and was introduced to North
America in the 1930’s.
Most likely to be found in…
• They are most likely to be found near
areas with large amounts of water like
lakes, streams, ponds, marshes, bayous
and swamps.
http://www.geocities.com/Heartland/Farm/7720/nutria.html
Description
• When full grown, nutrias are about 2 feet
•
in length excluding the tail. The average
adult weight is 18 to 25 pounds.
They are semi-aquatic rodents with webbed hind
feet and appear to be equally at home in fresh
or salt water, warm or cold.
• http://www.geocities.com/Heartland/Farm/7720/
nutria.html
SMILE!
• Nutria rats have 2 upper and 2 lower
incisors which are razor sharp. They use
these to gnaw on plants.
http://www.geocities.com/Heartland/Farm/7720/nutria.html
Main food source
• Nutria are almost entirely herbivorous and eat
animal material (mostly insects) incidentally,
when they feed on plants. Freshwater mussels
and crustaceans are occasionally eaten in some
parts of their range. Nutria are opportunistic
feeders and eat approximately 25% of their
body weight daily. They prefer several small
meals to one large meal.
http://www.extension.org/faq/973
Food source continued…
• Their natural food consists almost entirely
of aquatic and semi aquatic vegetation,
but when these animals live along the
coast they also feed upon shellfish.
Cattails, reeds, and sedges appear to be
especially prized items of food. When
established near gardens, they take
cabbage readily; they are also fond of
carrots and sweet potatoes.
http://www.nsrl.ttu.edu/tmot1/myoccoyp.htm
Reproduction:
• A female nutria averages about five young
per litter, but can birth as many as 13 at a
time. A female can breed again within two
days after giving birth, meaning one nutria
can have up to three litters per year.
http://www.sciencedaily.com/releases/2008/
03/080306094624.htm
Reproduction continued…
• The gestation period is from 127 to 132 days. At
birth the young are fully furred, and their eyes
are open; they are able to move about and feed
upon green vegetation within a few hours. At
that time they weigh approximately 200 g. They
mature rapidly, increasing at the rate of about
400 g per month during the first year, and reach
sexual maturity at the age of 4 or 5 months.
Females sometimes give birth to their first litter
when they themselves are 8 or 9 months old.
http://www.nsrl.ttu.edu/tmot1/myoccoyp.htm
Predator vs. Prey
• There are only two predators for the nutria rat
– Alligators
– Humans
• Preys of the nutria rat consist of:
–
–
–
–
Snakes
turtles
Gar
some raptors
• http://www.geocities.com/Heartland/Farm/7720/nutria.h
tml
Relatives
• Beavers are relative to the nutria rat, and
in which sometimes the nutria rat is
mistaken for a beaver because of their
similar characteristics.
Differences
• The tail of the nutria is round and nearly
hairless like the tail of the common lab rat
while the beaver's tail is flat; nutrias have
a far better disposition than beavers do
both in the wild and in captivity.
http://www.geocities.com/Heartland/Farm/7720/nutria.html
Competition with muskrats
• Because of their known competition with
muskrats, which are well-established and
valuable fur-producing animals in this
country, it appears that muskrats may be
driven out and replaced by the much less
desirable nutria
Interesting facts
• An interesting fact about nutrias is that
the mammary glands of the female are
located high on the back, NOT on the belly.
This facilitates feeding the young in their
aquatic environment. Because nutrias
reproduce so quickly (one female can
produce up to 150 young in 16 months and
they appear to breed year round), they
quickly exhaust the food supply in their
areas and have to move on.
http://www.geocities.com/Heartland/Farm/7720/nutria.html
More facts
• They are almost entirely nocturnal,
consequently their presence in an area
usually is revealed only by their trails,
feces, and lengths of cut vegetation that
have been left in their trails.
http://www.nsrl.ttu.edu/tmot1/myoccoyp.htm
Problems
• The feeding habits of the nutria cause millions of
dollars of damage yearly. Both rice and cane
farmers experience problems with this nomadic
rodent and even home gardeners will find that
cabbage, carrots and sweet potatoes may attract
these hungry herbivores.
• http://www.nsrl.ttu.edu/tmot1/myoccoyp.htm
More problems…
• They do reduce many kinds of aquatic plants, but they
will not eat "moss" (algae) and many of the submerged
plants. At times they do the job too well. The trouble is
that once nutrias get established in a lake, their high
reproductive capacity soon results in overpopulation.
There are so many nutrias that the available food supply
will not satisfy them, and then trouble begins. The
animals move into places where they are not wanted or
where they destroy vegetation that is valuable for such
wildlife as waterfowl and muskrats
http://www.nsrl.ttu.edu/tmot1/myoccoyp.htm
Life span…
• The maximum length of life for nutria kept
in captivity is 12 years, but the life span in
the wild probably is considerably less.
Pictures