Smooth-coated otters are a Palearctic and Oriental species. They are found throughout much of southern Asia, from India eastward. There is also an isolated population found in the marshes of Iraq. Evidence shows that the range and population of smooth-coated otters is shrinking due to loss of habitat and intensive trapping.
Biogeographic Regions: palearctic ; oriental
Smooth-coated otters are the largest otters in southeast Asia. They weigh from 7-11 kg as adults and can be up to 1.3 m long. Their fur is shorter and smoother than other otters, and appears velvety and shining. They have short tightly packed under fur and longer water repellant guard hairs. The under fur measures 6-8mm, the guard hairs are 12-14 mm long. The fur is light to dark brown dorsally, and light brown to almost gray ventrally. Smooth-coated otters are distinguished from other otters by their rounder heads, prominent naked noses, and flattened tails. Their noses resemble an upside down v, or a distorted diamond. Like other otters, they have webbed feet and strong dexterous paws that are armed with sharp claws.
Range mass: 7 to 11 kg.
Range length: 1 to 1.3 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Smooth-coated otters are mostly found in lowlands, coastal mangrove forests, peat swamp forests, freshwater wetlands, large forested rivers, lakes, and rice paddies. Although adapted for water, smooth-coated otters are equally comfortable on land and can travel long distances overland in search of suitable habitat. They shelter in shallow burrows and piles of rocks or driftwood. Some build permanent burrows near water with an underwater entrance and a tunnel that leads to a chamber above the high-water line, much like American beaver. In Malaysia smooth-coated otters are more abundant in mangrove forests than in river systems.
Habitat Regions: temperate ; freshwater
Terrestrial Biomes: forest
Aquatic Biomes: lakes and ponds; rivers and streams; temporary pools
Other Habitat Features: riparian
Habitat and Ecology
Along the large rivers in India, the smooth-coated otters prefer rocky stretches since these stretches provide sites for den and resting. River stretches with bank side vegetation and marshes are used in proportion to their availability especially in summer as they provide ample cover while travelling or foraging. Open clayey and sandy banks are largely avoided as they lack escape covers (Hussain 1993, Hussain and Choudhury 1995, 1997). In the Tarai areas of the upper Gangetic plains the smooth-coated otters use seasonally flooded swamps during monsoon (July-September) and in early winter (October-February). Winter being the breeding season, the swamps are extensively used as natal den sites and nursery. By February-March the swamps begin to dry and the fish biomass appears to be depleted, consequently the otters move to the perennial rivers (Hussain 1997). In west Java, the smooth-coated otters prefer mangroves and tidal stretches of the rivers and rice fields. Freshwater swamps and coastal stretches lacking vegetation are avoided (Melisch et al. 1996). In rice fields and pond areas they prefer sites having moderate diversity of vegetation. Rivers with moderate to slow or stagnant water and water bodies having a width of 10-40 m are preferred. In Huai Kha Khaeng, Thailand, the smooth-coated otters extensively use the slowly meandering river near the dam and the dam itself (Kruuk et al. 1994).
The smooth-coated otter is predominantly a fish eater, but supplements its diet with shrimp/crayfish, crab and insects, and other vertebrates such as frog, mudskippers, birds and rats (Prater 1971, Foster-Turly 1992, Hussain and Choudhury 1998). In general, its diet is similar to that of Eurasian otter. The range of fish in the diet varies from 75% to 100% (Tiler et al. 1989, Foster-Turly 1992, Hussain 1993, Melisch et al. 1996, Hussain and Choudhury 1998).
The smooth-coated otters exhibit the typical opportunistic feeding behaviour similar to the Eurasian otter. Along the major rivers in India they eat more fish, often making up to 94% of the total diet (Hussain and Choudhury 1998), while along the coast in mangrove habitats and in rice fields it ranges between 75-100% (Foster-Turly 1992, Melisch et al. 1996). In west Java otters inhabiting mangrove areas eat more of crustaceans, around 22% of the scats contain remains of crab and shrimp where as in the paddy fields in Malaysia, along with fish they tend to eat more rice field rats Rattus argentiventer, represented in 23% of the spraints (Foster-Turly 1992).
Hussain (1993) identified 12 fish species from the spraint of smooth-coated otter from Chambal river, of which seven species were eaten throughout the year. Rhinomugil corsula (Mugilidae) and Rita rita (Bagaridae) were the preferred species. At least eight species of fish were identified from the spraints from Malaysia (Foster-Turly 1992). Some of these include Gourami (Trichogater spp.), climbing perch (Anabis testudineus), catfish (Clarius spp.), snakehead (Channa spp.) and mudskipper (Gobioidei). Along the rice field they ate large amount of most common fish (Trichogater and Anabis spp.). The size of the fish consumed varied from 5-46 cm, often ranging between 15-30 cm (Wayre 1978). No significant relationship was found between the calorific values of the fish and the quantities consumed. Thus, the prey selection by smooth otter is mainly influenced by its availability (Hussain 1993).
The smooth-coated otter attains sexual maturity at twenty-two months in captivity (Desai 1974). Yadav (1967) observed first litter at four years of age. In captivity they mate during August to October in water followed by prolonged playful bouts between partners (Desai, 1974, Naidu and Malhotra 1989). Copulation takes place several times daily. Males are polygamous mating with up to four females (Desai 1974). In the wild in northern India mating occurs in August-September and littering in November-December (Hussain 1993). Desai (1974) observed litter size of 2-5 (mean = 3.25). Similarly, Naidu and Malhotra (1989) observed litter size 1-5. The breeding schedule of smooth otters in the wild in India corresponds with the captive records (Hussain 1993, 1996). Evidences of littering have been recorded in October and the cubs were seen out of the den in February. The mean litter size along the Chambal river was three (Hussain 1996).
Based on the percentage of active telemetry recordings, Hussain (1993) observed that the overall activity pattern of smooth-coated otters along the Chambal River in India was in the form of a bimodal curve in which two period of high activity were separated by a period of relative inactivity. This pattern of activity varied considerably among seasons. In summer, the relative period of inactivity was greater than in winter or monsoons. A significant difference was also found between day and night time activities in different seasons. Otters were more diurnal during winter than in summer or monsoon.
Hussain (1993) observed daily movements of four radio-implanted smooth otters of different age and sex within their home range. Two types of movements were identified; small-scale movements associated with foraging in a restricted area close to dens, and more extensive travels between dens and foraging sites. Most of the movement was restricted between 250 to 1500 m. A typical group of smooth-coated otter consisting of male, female, and up to four young ones require 7 to 12 km of river for their territory and an even longer stretch of shoreline if living along the coast (Wayre 1974). During a radio-tracking study along the Chambal River, India, the home range of all the otters tracked overlapped intensively. Among the radio-implanted otters, the maximum home range was observed in sub-adult male and the minimum in juvenile female and male. Among the non-tagged otters, the home range of female with cubs was estimated as 5.5 km. In case of the adult male it was estimated to be approximately 17 km (Hussain 1993). Along the Chambal River, the home range length and area of smooth-coated otter was less than that of Eurasian otter, in Perthshire, Scotland and Northern river otter Lutra candensis in Idaho (Melquist and Hornocker, 1983), but larger than that of Eurasian otter (Erlinge 1967) in Sweden.
Depth range (m): 0 - 0
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Smooth-coated otters are omnivorous and will eat insects, earthworms, crustaceans, frogs, water rats, turtles, large birds, and fish. Fish make up 75 to 100% of the diet. Smooth-coated otters frequently hunt in groups, driving schools of fish together for easy capture. Fishermen in India and Bangladesh use this group hunting behavior to train them to herd fish into nets. A group of otters has a feeding territory of 7 to 12 square kilometers. A single adult consumes about 1 kg of food per day in captivity.
Animal Foods: birds; mammals; amphibians; reptiles; fish; eggs; mollusks; terrestrial worms; aquatic or marine worms; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Smooth-coated otters impact aquatic vertebrate and invertebrate communities via predation.
Saltwater crocodiles and other crocodile species are the most likely predators of smooth-coated otters. Other potential predators are medium-sized cat species and large birds of prey (primarily on young otters). Smooth-coated otters are agile in the water and on land and use their sensitive whiskers to detect water disturbances. They are also social animals, with each animal in a group contributing to vigilance efforts.
- saltwater crocodiles (Crocodylus porosus)
Known prey organisms
This list may not be complete but is based on published studies.
This list may not be complete but is based on published studies.
Life History and Behavior
Like other carnivores, smooth-coated otters use scent for inter and intra specific communication. They have a pair of scent glands at the base of the tail, which they use to mark vegetation, flat rocks, or shorelines near feeding areas. This marking behavior in otters is called sprainting. In areas where the smooth-coated otter, European otter, and small-clawed otter occur together, sprainting occurrs in different areas by each species. Sprainting sites in small-clawed otters are usually high on the bank on flat rocks. Sites for smooth-coated otters are more prominent than those of small-clawed otters. Sprainting sites of European otters are lower on the bank and less frequent than that of other otters.
Smooth-coated otters also use visual cues, such as body postures, touch, and auditory cues in communicating with conspecifics.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
The oldest known smooth-coated otter in captivity died at 20 years and five months. The typical lifespan in the wild is between 4 and 10 years, although no conclusive studies have been made. It is suggested that the mortality rate of smooth-coated otters is correlated with the abundance of fish. Smooth-coated otter populations follow fish populations in the Tarai areas of the upper Gangetic plains in India and Nepal. Following the monsoon season, smooth-coated otters move into flooded swamp areas to take advantage of fish population booms. The otters breed there and when the swamps shrink and the fish return to the permanent rivers so do the otters.
Status: captivity: 20 (high) years.
Status: wild: 4 to 10 years.
Lifespan, longevity, and ageing
Smooth-coated otters form strong monogamous pairs. Although males are larger, it is females that dominate the pair.
Mating System: monogamous
No conclusive studies have been made on reproductive timing in smooth-coated otters. Where otters are dependent on monsoons for precipitation, they are most likely to breed between August and December. In the Delhi Zoo, all matings occurred in the month of August. The gestation period is 61-65 days. Smooth-coated otters give birth to and raise their young in a burrow or shelter near water, which they excavate, or they assume an abandoned one. The cubs disperse at about 1 year of age. Sexual maturity is reached at two years.
Breeding interval: Breeding occurs once yearly.
Breeding season: Breeding occurs from August to December.
Range number of offspring: 2 to 5.
Range gestation period: 61 to 65 days.
Average weaning age: 130 days.
Average age at sexual or reproductive maturity (female): 2 years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average number of offspring: 5.
Two to five cubs are born in a litter, blind and helpless. At thirty days, the cub's eyes open, and by sixty days, they can swim. The young are weaned at about 130 days. Unlike other otters, smooth-coated otters form small family groups consisting of a mated pair with up to 4 offspring from previous seasons. The male is allowed to join the group after the cubs are weaned, and he helps provide the cubs with food.
Parental Investment: altricial ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents
Smooth-coated otters are listed as vulnerable on the IUCN Red list. The population is threatened by loss of wetland habitats to large-scale hydroelectric projects, settlements and agriculture, poaching, and contamination of waterways by pesticides. Smooth-coated otters are protected in India under the Wildlife (Protection) Act, 1972, and are listed as endangered. They are also listed under schedule II, and listed in Appendix II of CITES.
US Federal List: threatened
CITES: appendix ii
IUCN Red List of Threatened Species: vulnerable
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1994Insufficiently Known(Groombridge 1994)
- 1990Insufficiently Known(IUCN 1990)
- 1988Insufficiently Known(IUCN Conservation Monitoring Centre 1988)
The smooth-coated otter, once common in the wetlands and low lying areas of South Asia, is now restricted to a few protected areas. Creation of networks of Protected Areas, identification of sites as wetland of national and International importance under Ramsar Convention has to some extent halts the degradation of its habitat.
Over the years the IUCN SSC Otter Specialist Group has developed a cadre of biologist across Asia to conduct field surveys and has popularize otter conservation by promoting otter as ambassador of the wetlands. However, concerted effort to conserve this species is needed. For the long term survival of the species, policy based action, research on factors affecting its survival, habitat based action on creation and where required expansion of protected areas and communication and awareness building actions are needed.
Relevance to Humans and Ecosystems
Smooth-coated otters do not negatively affect humans.
Like other otters, smooth-coated otters are trapped for fur. Although not as luxurious as its North American cousin, the river otter, or the sea otter, the pelage of smooth-coated otters is used for garments, adornments, and other items. Trained smooth-coated otters are used by fisherman to herd fish into nets.
Positive Impacts: body parts are source of valuable material
The smooth-coated otter (Lutrogale perspicillata) is a species of otter, the only extant representative of the genus Lutrogale. The species is found in most of the Indian Subcontinent and eastwards to Southeast Asia, with a disjunct population in Iraq. As its name indicates, the fur of this species is smoother and shorter than that of other otters.
Smooth-coated otters are relatively large for otters, from 7 to 11 kilograms (15 to 24 lb) in weight and 59 to 64 centimetres (23 to 25 in) in head-body length, with a 37 to 43 centimetres (15 to 17 in) tail. They may be distinguished from other species of otter by a more rounded head and a hairless nose in the shape of a distorted diamond. The tail is flattened, in contrast to the more rounded tails of other species. The legs are short and strong, with large webbed feet bearing strong claws. As their name suggests, they have unusually short and sleek fur; this is dark to reddish brown along the back, while the underside is light brown to almost grey in color. Females have two pairs of teats.
Distribution and habitat
Smooth-coated otters occur throughout much of the Indian Subcontinent and contiguous regions of Southeast Asia, in the Indomalaya ecozone. An isolated population of the species is also found in the marshes of Iraq.
Smooth-coated otters are found in areas where fresh water is plentiful — wetlands and seasonal swamps, rivers, lakes, and rice paddies. Where they are the only species of otter, they may be found in almost any suitable habitat, but where they are sympatric with other species, they avoid smaller streams and canals in favour of larger bodies of water. They have adapted to life in an aqueous habitat, but are nonetheless comfortable on land, and may travel long distances overland in search of suitable habitats.
Although they are often found in saltwater near the coast, especially on smaller islands, they require a nearby source of fresh water.
- L. p. perspicillata – most of India, Nepal, southwestern Yunnan, most of Southeast Asia, Sumatra, Java
- L. p. maxwelli – southern Iraq
- L. p. sindica – Sindh
Fossils belonging to the genus Lutrogale are known from the early Pleistocene of Java. Two fossil species, an earlier form, L. robusta, and the more recent L. palaeoleptonyx, are known, and may have fed primarily on shellfish, rather than on fish as the current species does.
Ecology and behavior
They spend the night in dens dug in dense vegetation, under tree roots, or among boulders. They use scent to communicate both within the otter species, and with other animals. Each otter possesses a pair of scent glands at the base of the tail which are used to mark land or objects, such as rocks or vegetation, near feeding areas in a behavior called sprainting. They also communicate through vocalisations such as whistles, chirps, and wails.
Some may construct permanent holts near water, in a layout similar to that of a beaver dam, with an underwater entrance and a tunnel that leads to a nest above the water.
Fish comprise over 70% of their diet, but they also eat reptiles, frogs, insects, crustaceans, and small mammals. Especially in areas where other species of otter are also found, they prefer larger fish, typically between 5 and 30 centimetres (2.0 and 11.8 in) in length. They sometimes hunt in groups of up to eleven individuals.
In the Kuala Selangor Nature Park an otter group was observed hunting. They formed an undulating, slightly V-shaped line, pointing in the direction of movement and nearly as wide as the creek. The largest individuals occupied the middle section. In this formation they undulated wildly through the creek, causing panic‑stricken fish to jump out of the water a few metres ahead. They suddenly dived and grasped the fish with their snouts. Then they moved ashore, tossed the fish up a little on the muddy part of the bank, and swallowed it head‑first in one piece.
So long as there is a sufficient food supply, they will breed throughout the year, but where otters are dependent on monsoons for precipitation, breeding occurs between October and February. A litter of up to five pups are born after a gestation period of 60 to 63 days. However, on 14 June 2014 a smooth coated otter called Ping at Wingham Wildlife Park in the UK gave birth to a litter of seven babies. The mothers give birth to and raise their young in a burrow near water. They may either construct such a burrow themselves, or they may take over an abandoned one. At birth, the pups are blind and helpless, but after 10 days, their eyes open, and they are weaned at about three to five months. They reach adult size at about a year of age, and sexual maturity at two or three years.
Major threats to Asian otter population are loss of wetland habitats due to construction of large-scale hydroelectric projects, reclamation of wetlands for settlements and agriculture, reduction in prey biomass, poaching and contamination of waterways by pesticides. In most Asian countries increased human population during the last century, inadequate and ineffective rural development programmes have not been able to address the problems of poverty, forcing people to be more and more dependent on natural resources. Consequently, most of the wetlands and waterways do not have adequate prey base for sustaining otter populations. Wetlands and waterways are polluted by eutrophication and accumulation of persistent pesticides such as chlorinated hydrocarbons and organophosphates through agricultural runoffs. Increased pesticide use is not only regarded as a major obstacle to the development of rice-fish culture, but also poses a danger to all predators feeding on aquatic prey in the area. In the entire south and southeast Asia there is severe conflict between otters and humans, because of poverty and recent increase in aquaculture activities leading to indiscriminate killing of otters. Many important habitats of smooth otter have been lost to development activities. In south east Asian countries, there does not seem to be any intentional otter trapping though it is prevalent in India, Nepal and Bangladesh.
Due to the draining of the Mesopotamian Marshes during the presidency of Saddam Hussein it was feared that the Iraqi population of otters may have perished. A biodiversity site review in 2009 found tracks of an otter, suggesting that the population may have survived, and comprehensive surveys in 2005–2012 found that it survived at several locations (even extending its range to Iraqi Kurdistan, far north of its previously known distribution).
Since 1977, Lutrogale perspicillata is listed on CITES Appendix II. It is a protected species in almost all the range countries, which prohibits its killing. But most range countries are not able to control the clandestine trade leading to extensive poaching.
The smooth-coated otter is listed as a vulnerable species. Their range and population are shrinking due to loss of wetland habitat and contamination of waterways by pesticides. Most range countries are not able to control the clandestine trade leading to extensive poaching. Smooth-coated otters are protected in India under the Wildlife (Protection) Act, 1972, and are listed as endangered.
Smooth-coated otters are used for commercial fishing in southern Bangladesh. These otters are bred in captivity, trained, and used to chase fish into fishing nets. This fishing technique is currently used by about 300 fishermen, with an additional 2,000 people indirectly dependent on the technique for their livelihood.
The smooth-coated otter was featured on the BBC documentary, Planet Earth, in the episode entitled "Fresh Water" (aired in the UK on March 19, 2006 and in the US on April 15, 2007). In this episode, it is shown openly pestering an adult crocodile.
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