University of California
Type of paper: Thesis/Dissertation Chapter
American River Otter in Zoo Setting
Otters are endemic to America and stay in American river systems. They can be found in all Watersheds of America. Moreover, their decrease is attributed to unregulated harvest, water pollution and habitat destruction. As a result, river otters have now become an endangered species. Nevertheless, Otters are still maintained by most people as pets, making them an interesting species. As a matter of fact, otters are the favorite animals in many zoo collections. However, they are also difficult to keep in a healthy condition and surprisingly there is very little knowledge about them. Otters are held in captivity for the purpose of breeding for likely reintroduction into the wild and for public education. This paper focuses on American river otters.
Geographical, Classification and Range
American river otters can be found in Alaska, inland waterways and coastal areas of Canada, the Pacific Northwest, the Atlantic State and the Gulf of Mexico. Otters belong to the family Mustelidae, which comprises mink, badgers, skunks, martens, wolverines and weasels. They are categorized under the subfamily Lutrinae, which has a total of thirteen species in six genera. The American otter exhibit permits visitors to observe the feeding habits and swimming capabilities of the otters. Moreover, visitors can see various species of otters in different colors frolicking in the water (Becker, 2002).
River otters are found in a variety of aquatic habitats, both in the coastal marine such as rivers, lakes, coastal shorelines, estuaries and marshes and in fresh water. The otter can tolerate a wide range of elevations and temperature. The primary needs of a river otter are a regular supply of food source and tranquil access to a body of water. They select their habitats grounded on the amount of shelter and food. It is for this reason that their habitat can change depending on the season. For example, they can move from temporarily flooded marshes to cypress swamps with permanent foods. Otters, are very sensitive to pollution, meaning that if the water is populated, the river otter will not be capable of surviving. It is for this reason that in captive setting, fresh and quality water is maintained. Growth of pollution, man-made poisons and cities destroy the otter habitat and decline their numbers (Niemuth, et al )
In most cases, river otters stay in a den or a holt, built in the burrows of other animals or in a natural hollows setting like in river banks, dens comprises of burrow dug by marmot monax, red foxes, nutria or beaver and muskrat lodges. They may also utilize logs or trees, rock creations, flood debris, undercut banks and backwater sloughs. The utilization of resting and den sites is primary opportunistic, though locations that gives seclusion and protection are highly preferred for otters. They also walk for great distances over land and through water to look for food. River otter; the weasel family hunt during the night and feed on whatever might be present. Fish are the favorite food for otters, though they also eat amphibians, crayfish and turtles. Otters love to playfully slide down snow-covered, muddy hills, or icy, which always end with a splash in the water. Pups enjoy such funs, which also demonstrates survival skills (Niemuth, et, al 2008).
River otters stay in a small family group when they have a litter of pups. Nevertheless, they have strict territories, which they preserve from others otters of the same sex. Male territories can overlap with female territories, but male territories do not overlap with other male territories. When families are comprised of an adult female and her offsprings, the male also introduces their own social groups. Nevertheless, females and males usually build separate hierarchies, putting up each other, but not escorting one another. Young pups love to play through wrestling and chasing one another. However, river otters do not have territories, and distinct groups tend to avoid one another.
Biological Tythms And/Or Migration, Navigation & Orientation
The river otters do go through a winter slow-down. They build ground beds or nests in hardwood swamps or dense thickets. Otters males and non-pregnant females do not appear to enter into a true hibernation. Rather, they enter a physiological state referred to as walking hibernation or denning. These otters will bed down for a few days, months or weeks, but they can be awakened on warm winter days for forage. Pregnant females go into hibernation state, especially in mid December to early January and do not awaken till late April or early May. Nevertheless, whether in a true hibernation or denning, the otters body temperature and metabolic and heart rates decline. The otters may lose up to 25percent of their body weight while hibernating (Williams et al, 2006).
River otters sexually mature between 2 to 3 years. In most cases, river otters mate in the fall or spring, with birth taking place the next year of mating. Nevertheless, river otters have deferred implantation cycle, which distinct them them from any other associated otter species. Though the gestation period takes around 60-63 days, the entire period of pregnancy can differ from 245-380 days.. The life cycle continues whereby the Otter pups weigh approximately 4.5ounces when born. The pup nurse for around 3 to 4 months and start to swim 2months after birth. It is natural for the young pups to swim, though the mother must lure them into the water for their first swim. The mother carries the pups on its back during the first days of swimming, thus coaxing them to swim. Usually, the pups move away from their mother when they are about 1 year old and ready to look for their own territory.
American river otters have adapted to an aquatic lifestyle just like fish. They are well fitted to dive and swim in water, just like how a dolphin fish does. However, otters have a slippery hydrodynamic nature, which exemplifies the perfect adaptation to an amphibious culture. As mentioned earlier, their webbed feet help them to swim with small dexterous front feed and large powerful hind feet. The muscular tail is somehow thick and flat at the base, tapering to a point. River otters utilize their hind limbs and undulating movement of their tail as the primary source of propulsion through the water. As a matter of fact, they also utilize their forelimbs for paddling. The common features for all otters is that they contain sleek waterproof fur, short hair, which is soft and dense. They also have perfect vision, particularly underwater, which aid them to capture their prey such as fish. Another adaptation is that they have stiff whiskers that are very sensitive to water turbulence. (Niemuth et al, 2008) This helps them to find prey in muddy water or dark waters. Likewise, the thumbs on the front paws help them to move freely and can only be opposed when the otter is picking up, or holding small things such as when the otter is eating.
Social Systems and Communication of River Otters
River otters mostly forage in the water, where they hunt their prey, they are similarly on land because they can also run quickly. But, when they are moving on land, they bound in a sprinting fashion, with their backs bowed. Fortunately, they combine running with sliding in the mud, snow, or ice, whenever it is possible for them to do that. This makes them move fast and reach their destination, also, it has made them to be the most playful of the Mustelidae family. Nevertheless, river otters are also extremely vocal, and communicate with one another using diversity of calls such as staccato chuckles, twitters, chirps and buzzes (Niemuth et, al, 2008).
When river otters develops and become solitary, they utilize scent marking to differentiate territorial boundaries. This is because, they have a pair of scent glands at the base of their tail that provides them with a heavy musky smell. Scent is very important for the otters because it gives the convey, the identity, sexual receptivity and sex of the otters. During the breeding season a male otter can utilize the sex makings of a female in estrus for beyond eight kilometers. However, though otters can be tolerant of other otters, the male otters do not contest for breeding preferences. There also slight commonality of territorial boundaries between the otters adults of similar sex. However, males exercise slight commonality of territories of various females (Esbensen, 1993).
In conclusion, the river otters are one of the social carnivores in the world. It is clear because, the river otters in the zoo setting have been seen to tend to respond to human in distinct manner than do wild otters. The biggest threat to otter species is trapping excessive fur. Also, other species progresses to decline due to overfishing, destruction of the otters habitat and water pollution. Thus, the only hope for the future of the river otters is by breeding the otters in a zoo setting. Nevertheless, it is only the most perfect breeding program where the pups are brought up by their mothers on natural prey in a zoo setting, can hope to raise and breed otters than can successfully accommodate to wild status. Therefore, careful considerations should be taken when breeding the otters. Chasing of other otter species progresses worldwide, making the species become an endangered species. Today, all the otter species are now an endangered species, though the North American river otter is not considered and endangered species, but it is clear that its population has extremely decline.
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