| Endangered Species: River Otter |
A Christiansburg Elementary Project
Submitted by Andrew of Christiansburg Elementary School
Christiansburg, Virginia, U.S.A.
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River Otter
This image courtesy of Encarta 95 |
River Otter
This image courtesy of Virginia's Endangered Species |
Why Study This Topic?
What did I want to find out about the river otter?
I wanted to find out basic information about this animal. What it eats,
how large, what habits it has, where it lives, and what its predators are
that cause it to be endangered.
I chose this animal because it was one of the few Virginia
mammals endanger of becoming extinct which I could choose from to write
this report.
What Was Already Known
Before I searched, I already knew that the river otter
was a quite playful animal. I also knew that the otter's fur was its insulation.
I knew this because I had read about the Exxon Valdez oil spill. Many otters
died because oil covered their fur. The oil spill is the reason for endangerment
which I knew.
Search for Information
I searched for information in various places. One
simple thing I s earched was a book. I looked up the river otter in the
World
Book Encyclopedia, and I checked out a book that was all about the
river otter. I also used more a advanced machine to research from. This
machine is called a computer. I used a CD-Rom and the Internet.
I didn't encounter any problems while searching for information.
Description of Plant or Animal
The river otter is classified as Lutra canadensis.
The length of a river otter is 1.0 meter or greater. Otters reach the maximum
length at the age of three or four. It is a member of the weasel family
and is roughly the size of this type of mammal. The river otter is distinguished
from other river animals by its dark brown fur and some what paler fur
on its lips, throat, and chest. There is also a subspecies classified as
Lutra canadesis laxitina which is slightly larger and distinctly paler
in color than Lutra canadesis. The river otter is also recognizable from
other creatures as river otters have a streamlined body. They also have
short legs and webbed toes. Another characteristic is that the river otter
has small eyes and ears. River otters can swim at around seven miles per
hour (MPH) and dive to 35 feet. When the otter dive flaps of skin close-off
the otters nose as well as ears. This allows it to stay underwater for
two minutes or longer before it must come up for air. The otter has a very
dense coat - so dense that the coat has over 1,000 hair per square inch
which allows air to be trapped for insulation and water proofing. It has
this because the river otters do not have a thick layer of blubber like
whales and other creatures of the water. One of the biggest things about
the otter is that it has a long tapering tail which is thick at the base
and thin at the tip and helps the otter navigate through the water rapidly.
The tail measures 1,000 to 12,000 millimeters long. Males are larger than
females in most cases and have a mass which averages 5-10 kilograms. Weight
of an adult otter ranges from 11 to 33 pounds.
Surprisingly, the river otter spends two-thirds of the
time on land (Leopold says they live primarily in water). At two years
of age otters usually reach sexual maturity. Their reproductive cycle involve
a delayed implantation of the fertilized egg and an arrested period of
development. It also involves an embryo growth as well. This process is
not fully understood yet. As a result of delayed implantation there is
a gestation period of 290-380 days.
Following the birth of a litter, breeding occurs in early
spring. The river otters newborn pups blind, toothless, silky black, and
helpless. At birth, the pups weigh four to six ounces and have a length
of 8-11 inches long. The little creatures grow rapidly and are able to
emerge from the den at two months of age. Now they eat solid food, but
are still not weaned until they are three months old. Females care for
the litter.
By the time the young otter are five to six months old,
they are self-sufficient. However, the family remains together for at least
seven or eight months or just before the birth of a new litter. Yearling
otters can scatter up to 20 mile or more from where they were born.
Otter droppings are referred to as spraints. Did you know
that a king kept a pack of tame otters? King James I of England did keep
a pack of otters to catch fish for his table. He even appointed a "Keeper
of the King's Otters" to tend to them.
Habitat Requirements
Otters live in rivers lakes, and marshes. They can
survive in both freshwater and ocean environments. River otters can be
found throughout North America including cold Arctic and warm water area
such as the southwest United States. The river otters can live in coastal
waters, but that is very rare. The river otter has now been annihilated
from the Great Plains and a lot of the eastern interior and southwestern
states. It is either rare or extrapated in at least 15 states. The river
otter can survive in the Gulf states (such as Texas, Louisiana, or Mississippi).
River otters have been sited in 16 different countries. In Europe, there
is a species of river otter classified as Lutra lutra.
River otters can live no more than a few hundred meters
from the water. Clean and unpolluted waterways isolated from human contact
is preferred by the river otter. Their aquatic habitat consists of log
jams and submerged trees. These things provide the resting and feeding
part of their habitat. Abandoned beaver lodges and bank dens serve as the
river otter's den. Habitats must provide an abundant amount of prey such
as slow moving fish and crayfish. They can also eat crabs, shrimp, clams,
annelids, and aquatic insects. Small birds, frogs, salamanders, and some
small mammals like young rabbits, mice, and voles are also part of the
otter's diet. It has been claimed that the river otter is a significant
predator to the muskrat, but it doesn't seem that way to me. The river
otter's long whiskers do have a use. They are used to detect organisms
which are eaten by the mouth immediately after capture. Their habitat can
be as small as 5-square miles or as large as 30 square miles. This depends
on the amount of prey in the area. Another factor is breeding season. During
breeding season this area is much reduced.
Adaptations
The river otter is a playful animal who enjoys sledding
and frolicking in the ice and snow. They have been known to slide on their
stomach and into the water from the top of a hill or mound. River otters
are excellent swimmers and divers. As I said before, this allows them to
stay under the water for two minutes or more. These swimming abilities
allow them to easily escape their natural enemies. Unfortunately, these
delightful characteristics do not protect them against the pollution caused
by man.
Reasons for Endangerment
The habitat of the river otter is being jeopardized
by pollution, specifically oil spills. The river otter's fur gets matted
and loses its insulation properties when exposed to petroleum products.
As mentioned previously, the river otter is an endangered species. River
otters have been hunted for many years. Their fur is attractive and quite
durable. In 1983-1984, 135 otters were taken with an average selling price
of $1,871 per pelt. Due to over trapping, the otter's population has declined.
Restoration Actions
There are many restoration acts for the river otter.
One is educating fur trappers to the present endangerment of the river
otter. Another is to establish a reproducing population in a suitable environment.
I think people should improve equipment of oil tankers. For instance, engineers
could strengthen the hull of ships, so that if they hits some rocks, it
will still confine the oil in compartments. I also think that there should
more endangered species organizations. The organization I propose could
help stop pollution from factories from entering the environments of endangered
species, as well as other animals so that they don't become endangered.
What Was Learned
I learned a whole lot about the river otter. I learned
that it could swim at around seven miles per hour, and the otter has a
very thick coat. I also learned that there is a big problem that needs
to be fixed, and man is the biggest predator for all endangered species.
Conclusions From Research
By writing this report I gained some researching benefits.
One is that I am more aware of what is happening to endangered species.
Another is that I know now that humans have a responsibility to protect
our wildlife. I also gained confidence in myself. By writing this report,
I have some experience in writing reports, and as I grow older I can do
bigger reports.
Return to Mammals page.
If you would like to add to these Endangered Species
pages then email your contributions to Christiansburg
Elementary
© copyright 1997
Christiansburg Elementary |
Last updated on March 9, 1998
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