The North American river otter,
also known as the Northern river otter, is a widely distributed
mammal that inhabits waterways across North America. Once
one of the most common freshwater mammals on the North American
continent, its numbers have been greatly reduced due to hunting
and loss of habitat. It's a popular animal in zoos, as it
has a playful demeanor due to its ability to stand on its
hind legs and its inclination to slide down muddy or snowy
inclines as if enjoying the ride.
This semi-aquatic mammal's
range extends from Alaska in the American Northwest to
Florida and the Gulf of Mexico in the Southeast. They are
members of the Mustelidae family, which includes badgers,
weasels, and otters. They are found throughout the North
American continent wherever there are suitable rivers,
streams, estuaries, lakes, swamps or wetlands. Because
they must stay within 100 meters of water, they avoid the
arid regions of the American southwest. River otters living
along the coast sometimes venture into the sea to forage,
and so are not strictly freshwater mammals.
North American
otters have long, slender bodies with short legs and a
long, thick tail that tapers at the end. They are able
to stand up on their hind legs, using their muscular tails
as a kind of third leg to help them balance. Their feet
have sharp claws and are webbed for swimming. Their nostrils
can be closed while they swim underwater for several minutes
(?), hunting for fish or other food. Prominent vibrissae
(whiskers) extend from their muzzle and have an important
sensory function, as they help otters feel the movement
of prey in the water even when it's dark or the water is
murky.
North American river otters weigh between 5 kg (11
lbs) and 14 kg (31 lbs), with males being generally larger
than females. They measure from 97 cm (38 inches) to 152
cm (60 inches) including the tail, which makes up about
a third of their length.
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| Picture
of North American river otter,
northern river otter, or Canadian
river otter, Lontra canadensis |
Image
#: 029336 |
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Kingdom:
Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia/Canoidea
Family: Mustelidae/Mustelids
Genus: Lontra
Specific: canadensis
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The North American river otter's
fur is brown to nearly black, with a lighter colored underbody
and throat. The lighter shade extends to just below the
ears and nose on the muzzle. Their fur has a dense undercoat,
which provides warmth in cold water and northern climates.
River otters have been observed spending a lot of time
grooming themselves, which helps to maintain the insulating
qualities of their fur.
North American river otters eat
fish, amphibians, crayfish, snakes, insects, snails, shellfish,
and other prey they can catch in or near the water. They
use their mouths to catch food, and their paws for swimming,
maneuvering, grasping and digging. River otters are generally
active at night, but can be diurnal as well.
North American
river otters have a high metabolic rate and so must eat
a lot. They are sometimes blamed for decimating fish populations
at fish farms and in rivers popular with fishermen. However,
their fish diet is mostly slow-moving rough fish that are
not desired by fishermen, so direct competition with fishermen
is questionable.
North American river otters are somewhat
solitary and do not generally travel in groups, with the
exception of a mother and pups. They require a range of
60 to 80 kilometers of waterway, and they make use of it
all, as they circulate through their range constantly,
hunting for food. They deposit spraint (scat) and use scent
glands to mark their territory, but seem nevertheless to
be fairly tolerant of other otters they come in contact
with. They can attain a land speed of 18 mph.
The dens
of Northern river otters (called holts) are generally natural
hollows, spaces under fallen trees or rocks, or sometimes
the confiscated dens of other animals, such as muskrats
or beavers. They line their holts with fur, grass, moss,
tree bark and leaves.
They breed in March and April, but
due to delayed implantation of the fertilized egg in the
uterus, birth does not occur until the following winter
or spring. From one to six pups are born in their den,
which is always located conveniently to water. Pups open
their eyes after one month, begin to swim at 2 months,
and are weaned at 3 months. They reach sexual maturity
at 2 to 3 years of age, and live about 9 years in the wild
or up to 21 years in captivity.
Historically, otters were,
along with beaver, one of the animals most prized for their
fur in early-American times when the European market created
a huge demand for high quality pelts for the fashion industry.
Native Americans and colonial hunters alike responded to
the demand and reduced otter numbers throughout their historical
range by extensive hunting and trapping. In 1800, the peak
of the river otter hunt in America, about 65,000 river
otter pelts were harvested. By 1900, river otters were
virtually exterminated from 11 states and one Canadian
province.
While river otter numbers were severely depleted
due to over-hunting and habitat loss after the arrival
of European settlers, they are now protected in many parts
of North America and have been reintroduced into many areas
from which they were exterminated. Twenty-one states and
one Canadian province have initiated repopulation efforts.
The effort has been a success, and river otters have multiplied
so rapidly that controlled trapping is now permitted in
areas where otters are considered a nuisance. Records show
that over 7,000 river otters are harvested in the State
of Louisiana annually. Despite the successful repopulation
effort, river otters are still vulnerable to pollution
and loss of wetlands, so people must be vigilant in protecting
river otter habitats. The IUCN now lists Northern river
otters as Least Concern.
Taxonomists now put North American
river otters in the genus, Lontra, or New World otters.
Previously, they were grouped with Old World otters in
the genus Lutra. Because some sources use the old classification,
North American river otters are sometimes archaically described
as Lutra canadensis. Additionally, there are many presumed
subspecies of North American river otter. The following
list contains North American river otter names that have
appeared in taxonomy databases on the Internet. The list
is not presumed to be exhaustive, and subspecies names
are not all necessarily scientifically accepted.
Lontra
canadensis brevipilosus - Grinnell, 1914; California, Oregon
Lontra
canadensis canadensis - Schreber, 1776; New England, central
U.S., eastern Canada
Lontra canadensis chimo - Andersen,
1945; northern Labrador, northern Quebec
Lontra canadensis
degener - Bangs, 1898; Newfoundland
Lontra canadensis evexa
- Goldman, 1935; British Columbia (western slope of Rocky
Mountains)
Lontra canadensis extera - Goldman, 1935; Nagai
Island
Lontra canadensis interior - Swenk, 1920; upper
Mississippi River Valley (Kansas, N. Dakota, Minnesota)
Lontra
canadensis kodiacensis - Goldman, 1935; Kodiak Island,
Afognak Island (Alaska)
Lontra canadensis lataxina - Cuvier,
1823; New Jersey to South Carolina
Lontra canadensis mira
- Goldman, 1935; Alexander Archipelago (SE Alaska)
Lontra
canadensis nexa - Goldman, 1935; S. Idaho, SE Oregon, NE
Nevada
Lontra canadensis optiva - Goldman, 1935; Montague
Island, Hinchinbrook Island, Kenai Peninsula (Alaska)
Lontra
canadensis pacifica - Rhoads, 1898; Oregon, Washington,
W. British Columbia, SE Alaska
Lontra canadensis periclyzomae
- Elliot, 1905; Queen Charlotte Islands (British Columbia)
Lontra
canadensis preblei - Goldman, 1935; Mackenzie River basin
and Hudson Bay area
Lontra canadensis sonora - Rhoads,
1898; California, SE Nevada, SW New Mexico
Lontra canadensis
texensis - Goldman, 1935; lower Mississippi River Valley
(Louisiana, Texas)
Lontra canadensis vaga - Bangs, 1898;
Florida, S. Georgia
Lontra canadensis vancouverensis -
Goldman, 1935; Vancouver Island, San Juan Island
Lontra
canadensis yukonensis - Goldman, 1935; Bering Sea coast,
Yukon
Alternate names: Northern river otter, North American
otter, North American river otter, Canadian river otter,
Loutre du Canada, Nutria de Canada, Nutria Norteamericana
© Northern river otter information assembled from on-line
sources by Kevin
Miller on May 6, 2008 for Seapics.com.
http://en.wikipedia.org/wiki/Northern_river_otter
ttp://animaldiversity.ummz.umich.edu/site/accounts/information/Lontra_canadensis.html
http://www.otterspecialistgroup.org/Species/Lontra_canadensis.html
http://www.funet.fi/pub/sci/bio/life/mammalia/carnivora/mustelidae/lutra/index.html
http://depts.washington.edu/natmap/facts/river_otter_712.html
http://www.iucn.org/dbtw-wpd/html/Otter/4.html http://www.zoo.org/factsheets/river_otter/riverOtter.html
http://www.fws.gov/SOUTHWEST/REFUGES/oklahoma/wichitamountains/creature%20features/otter.html
http://www.ngpc.state.ne.us/wildlife/otters.asp
http://www.lioncrusher.com/animal.asp?animal=167
http://www.mikebottini.com/ http://www.hartfordinfo.org/issues/documents/history/htfd_courant_112005.asp
http://www.jstor.org/pss/3781676
http://www.jstor.org/pss/3801601 |
