Lutra sumatrana

Geographic Range

Hairy-nosed otters ( Lutra sumatrana ) are native to the Himalayan Mountains in the Oriental region. Their current range is limited to just six distinct, isolated regions in Southeast Asia. In Indonesia, the southernmost populations exist in the southern portion of Sumatra. The Sumatran population covers the south and eastern coasts, as well as Bangka Island. Across the Java Sea, a second population inhabits the island of Borneo (Malaysia, Indonesia, and Brunei). A third group inhabits the main island of Malaysia, from Singapore northwards to Surat Thani. A fourth group exists in the western third of Cambodia, continuing south into southern Vietnam. The fifth and sixth regions where hairy-nosed otters reside are small just west of Da Nang, Vietnam, and the northernmost reaches of Myanmar. Some of the hairy-nosed otters’ population have a residence in either a wildlife sanctuary, a nature reserve, or a national park. For instance, a fourth of the population in most southern parts of Thailand has been found in Hala Bala Wildlife Sanctuary, Narathiwat. All individuals in Vietnam are found in the U Minh Thuong Nature Reserve and the U Minh Ha National Park. A third of the population in Cambodia was found by the side of the coast at the Peam Krasop Wildlife Sanctuary and the Ream National Park.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Hairy-nosed otters live in terrestrial, freshwater, and marine habitats. In Thailand, hairy-nosed otters inhabit peat swamp forests that are seasonally-flooded wetlands with a dense overstory. They inhabit coastal areas of Southeast Asia, across much of their range, these otters are found in peat swamp forests, which provide access to plentiful food. Hairy-nosed otters also occupy forest areas with elevated water levels typically like the Tonle Sap Lake in Cambodia. A seasonally flooded forest, this species has been found in wet forest areas with places where it can swim, but the main areas are not accessible to humans.

Elevational ranges are reported to be sea level to 900 m asl.

• Habitat Regions
• tropical tropical
• freshwater freshwater

• Terrestrial Biomes
• forest forest

• Wetlands
• swamp swamp

Physical Description

Hairy-nosed otters have elongated bodies and webbed paws suitable for swimming. As their name suggested, they have a hairy nose pad. These otters weigh between 5 to 8 kg, exhibit an average total length of 61 cm and an average tail length of 34 cm. Hairy-nosed otters have fur that is dark brown with a white patch on their throats. They may also possess white on their chin and upper lip. These otters have large forepaws measuring 59 mm long and 57 mm wide, being symmetrical.

Male hairy-nosed otters are generally larger than females. In Thailand, this difference was quantified; female otters are 7 kg, and males are 8 kg. There are also geographical distinctions in size. For instance, Malaysian hairy-nosed otters are bigger than those in Sumatra.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Development

The developmental biology of hairy-nosed otters remains largely undocumented. However, Eurasian otters ( Lutra lutra ) and hairy-nosed otters likely exhibit similar developmental characteristics. Initially, development begins at the embryonic stage, during which female otters may exhibit a period of reduced activity lasting up to 10 months. This is followed by an approximate 2-month gestation period, giving birth during the spring season. Postnatally, female otters provide maternal care, remaining with the cubs for a period of months to ensure their survival and development. Like all mammals, these otters exhibit determinate growth.

Reproduction

Hairy-nosed otters are monogamous. Their mating season extends from November to March. Although mate selection is not described for hairy-nosed otters, anecdotal evidence from camera surveys suggests mates pair up only briefly during the breeding season. Mating selection and rituals have not been observed.

• Mating System
• monogamous monogamous

Hairy-nosed otters are suspected to breed once or twice yearly, from November to March. These otters have a gestation period of 2 months. Anecdotal data suggest they give live birth from April through June, as cubs are documented in April through July, and possibly November. But there is conflicting evidence; Wright et al. (2008) report these otters breed between November and December in Vietnam, with cubs present December to February. Hairy-nosed otters are iteroparous, thought to have 1-3 young per litter, based on camera survey data that captured one mother and three young, plus the discovery on one dead female with two embryos.

The age of sexual maturity for hairy-nosed otters is unknown. Related Eurasian otter ( Lutra lutra ) females start reproducing as young as 3-5 years old, with most litters occurring between the ages of 6-9 years.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Descriptive parental care for hairy-nosed otters is unknown, although females have been captured on camera with their cubs. A single camera photo showed two adults with cubs, suggesting males may play a role. However, it is likely that females primarily care for the youth and that the young stay with their mother for a period of months after their birth.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
• pre-independence

Lifespan/Longevity

Lifespan is not reported for hairy-nosed otters, but European otters ( Lutra lutra ) have been reported to live 18.2 years in captivity. Hairy-nosed otters are not kept in captivity. There are no reports for longevity in the wild for members of the genus Lutra . Based on other members of the genus, it’s likely that only a quarter of the individuals in the wild reach the age of 2.

Behavior

Behavior of hairy-nosed otters is not well-studied and instead based on anecdotal evidence and results of camera surveys. From these sources, hairy-nosed otters are presumed to live a solitary lifestyle outside of the breeding season. These otters move in groups of two to five and usually consist of a mother with cubs, parents with their cubs, or just a group of individual adults of unknown familiarity. A description of a single captive juvenile hairy-nosed otters suggests they are a social species. These otters do not migrate and are considered adept swimmers. Hairy-nosed otters swim underneath large fallen trees in rivers, and use their webbed paws to aid in this form of travel. These otters are primarily diurnal - active early in the morning and the afternoon. However, multiple camera studies reported variations in times of peak activity, and they have been documented nocturnally. In a Cambodian study, they were reported to be "cathemeral," meaning active both day and night. Here, activity was slightly more nocturnal or crepuscular.

They may rest on higher ground in thick reeds, and resting areas are described as a bird's nest – a flattened area surrounded by tall grasses.

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• social social

Home Range

Home range and territories have not been reported for hairy-nosed otters. Another member of the genus, Eurasian otters ( Lutra lutra ), have a reported range of 29.20 km^2. It is likely the hairy-nosed otters have a similar range.

Communication and Perception

Little is known about how hairy-nosed otters communicate and how they perceive the world around them. Hairy-nosed otters contact calls are a single syllabic chirp. It has been observed that mothers also make a staccato chatter (e,g,, short, detached, distinct sounds) to their young when calling them. They likely use tactile efforts to climb, swim, and catch prey, as well as mate and care for their young. They presumably use vision to locate prey and traverse their home range.

No information is known about how they communicate chemically with pheromones. However, they do leave scat piles on logs and stumps above the water line. They do not participate in creating large latrines among multiple individuals. These scat piles presumably leave territorial cues to other otters in the area.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Hairy-nosed otters are carnivores and are primarily piscivores, with diets upwards of 85% fish. They swim to their prey and scare the fish; when fish escape to the roots of a plant, the fish are tangled up for easy predation. The fish species diet varies by location; for instance, in Thailand the otters’ prey upon climbing perches ( Anabas testudineus ), three spot gouramis ( Trichogaster trichopterus ), and snakeheads ( Channa argus ). Hairy-nosed otters consume walking catfish ( Clarias batrachus ) in Vietnam and snakeheads during their dry season. Wright et al. (2008), report otters eating freshwater crabs ( Geothelphusa dehaani ) until crabs were overharvested by humans. Subsequently, hairy-nosed otters changed their diet to fish and snakes. Hairy-nosed otters historically included frogs, lizards, birds, and other small mammals as part of their diet.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • piscivore piscivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish

Predation

Animals that prey on hairy-nosed otters include grey-headed fish-eagles ( Ichthyopaga ichthyaetus ), stray dogs ( Canis lupus familiaris ), and reticulated pythons ( Python molurus ). Rarely Siamese crocodiles ( Crocodylus siamensis ) may prey on those otters in Cambodia. Humans ( Homo sapiens ) can also be predators as a result of illegal hunting. Other species of eagles (species not listed) and Burmese pythons ( Python molurus ) might prey on otters in Vietnam. There is no known information about how hairy-nosed otters avoid predation.

Ecosystem Roles

Hairy-nosed otters consume fish, crabs, and frogs, and are consumed by eagles, nnative crocodiles, and some pythons. No parasites have been documented for hairy-nosed otters, although European otters ( Lutra lutra ) are known to harbor cestodes and nematodes

Economic Importance for Humans: Positive

Hairy-nosed otters are traded illegally trade for their fur. Otter fur is sold in Vietnam and Cambodia and shipped to China for use in clothing. Occasionally, individuals are caught while fishing and are kept as pets. In Cambodia, some of the parts of the otter are used in traditional medicine, including the skin, fetuses, and gallbladders are used to fight fevers.

• Positive Impacts
• pet trade pet trade
• body parts are source of valuable material
• source of medicine or drug source of medicine or drug

Economic Importance for Humans: Negative

There are no known negative economic impacts that hairy-nosed otters have on humans.

Conservation Status

Hairy-nosed otters are listed as “Endangered” on the IUCN Red list. They have no special status on the US Federal List and the state of Michigan list. They are found in Appendix II on CITES, which regulated the international trade of these otters.

Threats to hairy-nosed otters include being caught and kept as pets and illegal trade of the otters for their fur and body parts. The otters are skinned, sold, and exported to places in high demand of them such as China to use the fur as part of their traditional costumes. Their value in pet trade is also on the rise, with high demand of these otters coming from Japan and Indonesia - so they are trapped and removed from Indonesia for in-country sale), plus Thailand and Vietnam (for illegal export). Population losses from 1990 to 2020 are estimated at 50%, with another 50% loss in remaining otters from 2020 to 2050.

Habitat destruction is a serious threat in Vietnam, Cambodia and Sarawak. In Cambodia, bout 50,000 ha of peat swamp forests have been converted to palm oil Elaeis guineensis plantations and two-thirds of the forests are now rice flats. In addition, climate change is leading to habitat destruction and therefore lack of food and water, and an increase in extreme weather. In Peninsular Malaysia, these otters have been hit by cars.

They are protected in the countries across their range. Hairy-nosed otters have been protected in Thailand and in the Phnom Tamau Wildlife Rescue Center in Cambodia. In Vietnam, otters hunting is prohibited. The illegal fur trade threatens population in Cambodia and Vietnam. Their illegal trade is prohibited nationwide since the 1990s, and has been enforced by wildlife management laws and regulation.

In Cambodia, the Ministry of Agriculture Forestry and Fisheries classified that hairy-nosed otters were rare, providing full protection of the species. Here, fishing is currently not heavily restricted because they are found in open waters in areas where the people are dependent on fishing and using other natural resources. However, Cambodia is in the early stages of implementing restrictions to protect the otters. Finally, in Sarawak, hairy-nosed otters are fully protected by the First Schedule Part II on the Protected Animals from the Wildlife Protection Ordinance in 1998, though there has been no record of how they are protected. They are rarely kept in zoos, and captive breeding has not been attempted. Just one hairy-nosed otter was reported to be in captivity in 2007 at the Phnom Tamau Wildlife Rescue Center. They do receive indirect protection when they exist in national parks, like they do in Vietnam.

Additional Links

Encyclopedia of Life

Contributors

Jaylen Rosser (author), Radford University, Natalie May (editor), Radford University, Alexander McVicker (editor), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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