Southern river otters, Lontra provocax, are only found in central and southern Chile and parts of Argentina. This species has been exterminated from much of its range in Chile by hunting. In Argentina, it is found along the Andes from Tierra del Fuego all the way to the southern part of Neuquen province (Otternet, 1998).
Biogeographic Regions: neotropical (Native )
L. provocax is a medium sized otter. It ranges from 1000 mm to 1160 mm in total length. Its tail is 350 to 460 mm long. These otters possess webbed feet with strong claws. Their hair has a velvety texture. The guard hairs range in length from 15 to 17 mm, and the under fur is 7 to 8 mm long. The dorsum is a very dark brown, which strongly contrasts with the silvery whitish ventrum. Their nose is diamond-shape with the bottom corner squared off (Otternet, 1998).
Range length: 1000 to 1160 mm.
Other Physical Features: endothermic ; bilateral symmetry
L. provocax inhabits both marine and fresh waters. It is found on rocky coasts and in protected canals in areas where there are few waves. It does not live in open coastal areas, but instead prefers coastal and freshwater environments with dense vegetation (Redford and Eisenberg, 1992).
Habitat Regions: terrestrial ; saltwater or marine ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams; coastal
Other Habitat Features: estuarine
Habitat and Ecology
It also occurs in marine habitats along southern Chile (Sielfeld 1983). Habitat in the Patagonian archipelago consists mainly of rocky coasts and canals protected from waves, where coastal strips of vegetation such as Drimis winteri, Notofagus betuloides, and Maytenus magellanica are present; these features, as well as reduced human disturbance, are thought to be favorable for the establishment of dens (Chehebar et al. 1986; Medina 1996a, 1996b; Sielfeld 1983). In Argentina, L. provocax is associated with dense mature forest with thick undergrowth extending close to shore. Both the above-ground root systems of mature or fallen trees and the dense vegetation cover are important components of L. provocax habitat; absence of these key features may result in absence of otters, even if abundance of prey is not limiting (Chehebar et al. 1986).
The southern river otter diet consists mainly of fish including such species as Cheridon australe, Cyprinus carpio, Galaxias, Notothenia, Oncorhynchus mykiss, Percichthys trucha, Percillia gillissi, Salmo trutta, as well as some crustaceans including Aegla, Camilonotus, Lithodes antartica, Munida, Paralomis granulosa, Parastacus pugnax, and Sammastacus spinifrom. Opportunistic consumption of mollusks (Diplodon chilensis, Fissurela) and birds has also been reported (Chehebar 1982; Chehebar and Benoit 1988; Medina 1996a, 1996b, 1997; Sielfeld 1983).
Breeding is thought to occur in July and August, and young are born in September and October (Housse 1953). In parts of the species' southern range, young can be observed all year (Parera 1996). Litter size average one or two young, but may litters of up to four young have been observed (Sielfeld 1983).
L. provocax diet varies within the separate habitat types. In a Chilean population, 75% of fecal samples analyzed had fish in them, and 63% had crustaceans. In Argentina the feces showed 99% of scats had crustaceans and only 2% contained fish (Medina, 1998). In addition to fish and crustaceans, southern river otters also eat mollusks and birds (Kruuk, 1995).
Animal Foods: birds; fish; terrestrial non-insect arthropods; mollusks
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)
This species probably acts as an important control on mollusk, fish, and crustacean populations.
Humans are known predators (Redford and Eisenberg, 1992). There are no reports of non-human predation on this species.
- humans (Homo sapiens)
This list may not be complete but is based on published studies.
Known prey organisms
This list may not be complete but is based on published studies.
Life History and Behavior
Perception Channels: tactile ; chemical
A high proportion of the individuals die before they reach maturity. Only about 1% will survive to reach 10 years of age. Most L. provocax only live a few years (Chanin, 1985).
Status: wild: 10 (high) years.
Status: wild: 3 (low) years.
Status: wild: >3 years.
The mating system of this species has not been reported.
River otters typically breed in the winter and spring, with births taking place the following year. Because there is a delay between mating and implantation of the fertilized eggs, there can be a great variability in the length of pregnancy. Although gestation has been reported to be 10-12 months long, actual embryonic development is around two months (Nowak, 1999).
Females have four nipples and produce one to four young each season, but usually produce only one or two young. L. provocax young are born a helpless, blind and scarcely mobile. Young spend their time in the den either suckling or sleeping. The milk is an extremely rich energy source and the young have a high metabolic rate. They open their eyes at approximately one month and begin to eat solid foods at 7 weeks. They begin to swim at about 3 months of age. They are usually capable of catching their own food within 4 months. The young remain with the family group for the first year before they disperse (Chanin, 1985). Reproductive maturity is attained in the second or third year of life.
Breeding season: Breeding occurs in the winter and spring, with births occuring the following year.
Range number of offspring: 1 to 4.
Average number of offspring: 1-2.
Range gestation period: 10 to 12 months.
Range age at sexual or reproductive maturity (female): 2 to 3 minutes.
Range age at sexual or reproductive maturity (male): 2 to 3 minutes.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous ; delayed implantation
As in all mammals, the female provides milk for her offspring. Young are altricial and are cared for by the mother until they disperse. Other aspects of parental care in this species are not known.
Parental Investment: altricial ; female parental care
Lontra provocax is listed as an endangered species. This is primarily due to illegal hunting, habitat loss and water pollution (Redford and Eisenberg, 1992).
CITES: appendix i
IUCN Red List of Threatened Species: endangered
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Vulnerable(Baillie and Groombridge 1996)
- 1994Vulnerable(Groombridge 1994)
- 1990Vulnerable(IUCN 1990)
- 1988Vulnerable(IUCN Conservation Monitoring Centre 1988)
- 1986Indeterminate(IUCN Conservation Monitoring Centre 1986)
- 1982Indeterminate(Thornback and Jenkins 1982)
Date Listed: 06/14/1976
Lead Region: Foreign (Region 10)
Where Listed: Chile,Argentina
Population location: Chile,Argentina
Listing status: E
For most current information and documents related to the conservation status and management of Lontra provocax, see its USFWS Species Profile
Concern about competition for food and space between Lontra provocax and the introduced American mink Mustela vison was raised when otter abundances were noted to be lower in areas where American mink were present (Chehebar 1985; Chehebar et al. 1986). It has been concluded, however, that competitive effects are unlikely to pose a major threat to the otter as the two species exhibit low overlap in diet (<26%) and habitats used (5-22%), suggesting that they may coexist with little competition (Chehebar and Benoit 1988; Chehebar et al. 1986; Medina 1997). Large scale destruction of forests in southern Chile may be affecting several of its freshwater habitats through severe flooding and deposition of soil on the river beds.
Reintroduction of southern river otters into areas where they were previously exterminated due to excessive hunting could be successful in the above mentioned enforcement of legislation and monitoring programs are carried out (Porro and Chehebar 1995; Medina 1996a). Conservation of the southern river otter will require better education, time allowance for populations to recover, and re-establishment of populations in native habitat (Medina 1996a, 1996b).
Relevance to Humans and Ecosystems
No negastive effects of this species on human populations has been noted.
Southern river otter
The southern river otter, Lontra provocax, is a species of otter that lives in Chile and Argentina. Although called a "river otter", it inhabits both marine and freshwater environments. It sometimes is considered a subspecies of Lontra canadensis. The southern river otter is listed as endangered, due to illegal hunting, water pollution, and habitat loss.
Physical characteristics[edit source | edit]
This medium-sized otter's body can grow up to 2.5 ft (70 cm) long, with a tail adding about 16 in (40 cm). Body weight averages about 5-10 kg (11-22 lbs). Its fur is dark-brown on the top and has a lighter cinnamon color on its underside.
Behavior[edit source | edit]
Although the female and her young will live in family groups, males are usually solitary. Litter sizes average one to two pups, but up to four can be born at a time. Their diets include fish, crustaceans, mollusks, and birds.
Habitat[edit source | edit]
The southern river otter can be found in marine, freshwater, and terrestrial habitats, but are mostly found in freshwater lakes and rivers having a significant amount of dense vegetation, especially along the shorelines, which must be present to use as cover. Their habitats also need the root systems of mature trees, as well as fallen tree debris.
Threats[edit source | edit]
Southern river otters were vigorously hunted for their pelts throughout the last 100 years. This is the major cause of their current low population numbers and endangered conservation status. Since then, they have not been able to recover due to a number of other threats. At this point, only seven known populations of this species are found throughout Chile and Argentina, and all of the populations are isolated from each other.
The riparian forests and rivers in which these otters are mostly found have been disturbed by human presence. Dam and road construction, as well as stream canalization and drainage for agriculture destroy many acres of what could be habitat for this species. Though Argentina began passing legislation in 1960 to outlaw the hunting of the southern river otter, hunting still does occur because of the lack of enforcement. Hunting is legal and does occur in Chile.
The continual decrease in prey numbers also causes problems for the southern river otter. Some invasive aquatic species that have been introduced into that area are limiting the mollusks and fish available for otter prey. This causes the otters to move to other freshwater systems to hunt for food.
Conservation[edit source | edit]
Several surveys and studies have been performed on the southern river otter to better understand its declining population numbers to be able to prevent the species from becoming extinct. Several of the known populations are found within national forests.
One survey in particular was performed to determine if any of this species live within these protected areas. The author surveyed three parks in Argentina: Lanin, Puelo, and Los Alerces National Parks. The surveyors spoke with people who live and work near these areas, and looked for prints and droppings of the southern river otter, while also looking for signs of the American mink. The mink was introduced into this area and is thought to compete with the southern river otter for food resources and habitat space. The results showed signs of the southern river otter were found in 32 of the 275 surveyed sites within the three parks. Of the 32 confirmed sites, 31 were of dense forest with thick undergrowth near the shorelines of freshwater systems. These results suggest having shoreline vegetation for cover is vital for their survival.
Future directions[edit source | edit]
Future directions for conserving this species include obtaining better information on the southern river otter’s population numbers and locations. If conservationists know where the individuals and families live, enforcement of antipoaching laws, as well as focusing on maintaining and protecting their habitats, will be easier. Captive breeding programs would also be beneficial for this species, to later reintroduce individuals into the areas where they were previously found.
References[edit source | edit]
- M. Sepulveda, M. Franco, G. Medina, L. Fasola & R. Alvarez (2008). "Lontra provocax". IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature. Retrieved 10 May 2012.
- Marcelo H. Cassini, Laura Fasola, Claudio Chehébar & David W. Macdonald (2010). "Defining conservation status using limited information: the case of Patagonian otters Lontra provocax in Argentina". Hydrobiologia 652 (1): 389–394. doi:10.1007/s10750-010-0332-6.
- M. A. Sepúlveda, J. L. Bartheld, C. Meynard, M. Benavides, C. Astorga, D. Parra & G. Medina-Vogel (2009). "Landscape features and crustacean prey as predictors of the southern river otter distribution in Chile". Animal Conservation 12 (6): 522–530. doi:10.1111/j.1469-1795.2009.00304.x.
- Claudio E. Chehébar, Adriana Gallur, Guillermo Giannico, María D. Gottelli & Pablo Yorio (1986). "A survey of the southern river otter Lutra provocax in Lanin, Puelo and Los Alerces national parks, Argentina, and evaluation of its conservation status". Biological Conservation 38 (4): 293–304. doi:10.1016/0006-3207(86)90056-X.
- L. Fasola, C. Chehébar, D. W. Macdonald, G. Porro & M. H. Cassini (2009). "Do alien North American mink compete for resources with native South American river otter in Argentinean Patagonia?". Journal of Zoology 277 (3): 187–195. doi:10.1111/j.1469-7998.2008.00507.x.
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