Endangered Species: River Otter

A Christiansburg Elementary Project
Submitted by Andrew of Christiansburg Elementary School
Christiansburg, Virginia, U.S.A.

river otter
River Otter

This image courtesy of Encarta 95

River Otter

This image courtesy of Virginia's Endangered Species

Why Study This Topic? What Was Already Known Search for Information Description of Plant or Animal Habitat Requirements
Adaptations Reasons for Endangerment Restoration Actions What Was Learned Conclusions from Research

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.


  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.

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Christiansburg Elementary
Last updated on March 9, 1998