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Domain
Eukaryota.
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Carnivora
Family
Mustelidae
Genus
Pteronura
Species
Lontra canadensis
Description


The River Otter, (Lontra canadensis) is a semi-aquatic mammal. The Length of average River Otters are 3.7 ft (males); 3.2 ft (females). The average weight are 11-30 lbs. Lifespan: Up to 8-9 years in the wild but are capable of 14 years; 21-25 years in captivity. A broad muzzle is found on the river otter's flat head, and the ears are round and inconspicu
ous. The rhinarium (nose) is bare, with an obtuse, triangular projection. Eyes of the animal are small and placed towards the front of the head. The river otter's nostrils and ears close during submersion, stopping water from entering them. Its vibrissae (whiskers) are long and thick, enhancing sensory perception underwater and on land. The fur of the species is short, The fur has a high luster and varies from light brown to black. The throat, chin, and lips are grayer than the rest of the body. Fur of aging river otters may become white-tipped, and rare albinos may occur.




Habitat


Although commonly called a "river otter", the North American river otter is found in a wide variety of aquatic habitats, both freshwater and coastal marine, including lakes, rivers, inland wetlands, coastal shorelines and marshes, and estuaries. It can tolerate a great range of temperature and elevations. A river otter's main requirements are a steady food supply and easy access to a body of water. However, it is sensitive to pollution, and will disappear from tainted areas. The North American river otter depends on other animals, living in a holt, or den, constructed in the burrows of other animals, or in natural hollows, such as under a log or in river banks. An entrance, which may be underwater or above ground, leads to a nest chamber lined with leaves, grass, moss, bark, and hair. The use of den and resting sites is just opportunistic, although locations that provide protection and seclusion are preferred. North American river otter is equally at home in the water and on land. It makes its home in a burrow near the water's edge, and can thrive in river, lake, swamp, or estuary ecosystems. Otter abodes feature numerous tunnels—one of which usually allows them to come and go from the water. Despite the wide variety of habitats in which the North American river otter can be found, they are particularly shy animals and will try to avoid human contact in the wild.





Predators and Prey


Prey is captured with a quick lunge from ambush, or sometimes after an extended chase. River otters can remain underwater for nearly 8 minutes, swim at speeds approaching 11 km/h (6.8 mph), dive to depths nearing 20 m (22 yd), and travel up to 400 m (440 yd) while underwater. Several river otters may even work together while fishing. Small fish are eaten at the surface, but larger ones are taken to the shore to be consumed. Live fish are typically eaten from the head. A highly active predator, the river otter has adapted to hunting in water, and eats aquatic and semi-aquatic animals. The vulnerability and seasonal availability of prey animals mainly influences its food habits and prey choices. River otters primarily eat fish. They are also known to eat whatever is easiest to find, like crustaceans, mollusks, insects, birds, oysters, shellfish, crabs, crayfish, frogs, rodents, turtles and aquatic invertebrates. When a supply of food dwindles or other prey becomes available, otters either transfer to a new location or convert their dietary choices to the most adequate prey





Native or Invasive


Based on my research, the River Otter is native to Vermont, tracing back to the 1800’s when their population size began to dwindle to to loss of habitat and over trapping, however over the years, they have made a comeback.





Form vs. Function

The river otter is physically well-equipped for aquatic life, the ears are short, the neck is the same diameter as the head, the legs are short and powerful, the toes are fully webbed, and the tail is tapered. These qualities give the river otter a streamlined profile in water, but reduce agility on land. The smell and hearing abilities of the river otter are acute. The otter has a delicate sense of touch in the paws in addition to great skill. Otters have specialized teeth, including sharp canines and carnassials (teeth adapted for tearing apart flesh) that inflict lethal bites to prey. Also, river otters have large molars used for crushing hard objects, such as the shells of molluscs. An adult river otter has a total of 36 teeth. All otters have very flexible bodies. This flexibility allows them to groom almost every inch of their fur and swim swiftly through water.






Interesting Facts

The North American river otter is more social than most mustelids, males may remain social even during the estrous period of females. Family groups may include helpers, which can be made up of unrelated adults, yearlings, or juveniles. Male river otters do not seem to be territorial, and newly dispersing males ma join established male groups. River otters deposit their strong scent all through out their territory to let other otters know they live there, it also communicates during the mating season that they're available and looking for a mate. River otters are active year-round, and are most active at night. They become much more nocturnal in the spring, summer, and fall seasons, and more diurnal during winter. River otters are renowned for their sense of play. Otter play mostly consists of wrestling with a member of its species. Chasing is also a common game. River otters rely upon play to learn survival skills such as fighting and hunting. Male river otters do not seem to be territorial, and newly dispersing males may join established male groups. While North American river otters are not endangered, their populations are still threatened by humans. It is still legal to trap river otters in 38 states, and anywhere from 20,000 to 30,000 individuals are killed each year for their pelts. Apart from the fur trade, the two largest threats to these animals are habitat destruction and water pollution. North American river otters very vocal, and the animals use a variety of calls to communicate. The calls may range from high-pitched chirps, whistles and twitters, to low grunting chuckles and buzzes.








Resources



1. North American River Otter, Retrieved November 15, 2012 from http://en.wikipedia.org/wiki/North_American_river_otter
2. North American River Otters, Retrieved November 15, 2012 from__http://animals.nationalgeographic.com/animals/mammals/american-river-otter/__
3. North American River Otter, Retrieved November 15, 2012 from __http://www.defenders.org/north-american-river-otter/basic-facts__
4. Otters - Physical Characteristics, Retrieved November 19, 2012 from, http://www.seaworld.org/animal-info/info-books/otters/physical-characteristics.htm
5. North American River Otter, Retrieved November 20, 2012 from
http://www.conservenature.org/learn_about_wildlife/otters/north_american_river_otter.htm