| Smooth-coated otter | |
|---|---|
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| In Borneo, Malaysia | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Suborder: | Caniformia |
| Family: | Mustelidae |
| Genus: | Lutrogale |
| Species: | L. perspicillata |
| Binomial name | |
| Lutrogale perspicillata (I. Geoffroy Saint-Hilaire, 1826) | |
 | |
| Smooth-coated otter range | |
| Synonyms | |
Lutra perspicillata | |
Thesmooth-coated otter (Lutrogale perspicillata) is a freshwaterotter species from regions ofSouth andSouthwest Asia, with the majority of its numbers found inSoutheast Asia. It has been ranked as "vulnerable" on theIUCN Red List since 1996, as it is threatened byhabitat loss,pollution ofwetlands andpoaching for theillegal wildlife trade.[1] As the common name indicates, itsfur is relatively smooth, and somewhat shorter in length than that of other otter species.
The smooth-coated otter has a short, sleek coat of dark-brown to reddish-brown fur along its back, with lighter grayish brown on its underside. It is distinguished from other otter species by a more "rounded" head, and by having a vaguely diamond-shaped, hairless nose. The tail is flattened, in contrast to the more rounded or cylindrical tails of other otters. The legs are short and strong, with large, webbed feet bearing strong and sharp claws for handling slippery fish. The smooth-coated otter is a relatively large otter species, weighing from 7–11 kg (15–24 lb) and measuring around 59–64 cm (23–25 in) in head-body length with a 37–43 cm (15–17 in) long tail. Females have two pairs of teats with which they nurse small litters of several young.[2]
Lutra perspicillata was thescientific name proposed byIsidore Geoffroy Saint-Hilaire in 1826 for a "brown" otter collected inSumatra.[3]Lutrogale was proposed as the generic name byJohn Edward Gray in 1865 for otters with a more convex forehead and nose, usingperspicillata as thetype species.[4] By the 19th and 20th centuries, several earlyzoological specimens were described, including:
The smooth-coated otter is the only living species in themonotypic genusLutrogale. Three regionalsubspecies are currently recognised:[2]
The smooth-coated otter, together with theAsian small-clawed otter and theAfrican clawless otter, form asister clade to the genusLutra. The smooth-coated otter and the Asian small-clawed ottergenetically diverged about 1.33 ± 0.78 million years ago.Hybridisation of smooth-coated otter males with Asian small-clawed otter females has occurred inSingapore. The resulting offspring and their descendants then bred back into the smooth-coated otter population, but maintained the genes of their small-clawed otter ancestors. Today, an urban population of at least 60 hybrid otters exists in Singapore.[9]
The smooth-coated otter is distributed inPakistan,India,Nepal,Bhutan,Bangladesh,southern China,Myanmar,Thailand,Cambodia,Vietnam,Peninsular Malaysia,Singapore, and onBorneo,Sumatra andJava. An isolated population lives in the marshes ofIraq.[1]It has often been recorded in saltwater near the coast, especially on smaller islands, but requires a nearby source offreshwater.[10]It inhabits areas where fresh water is plentiful such aswetlands, seasonalswamps, rivers, lakes andrice paddies. Where it is the only occurring otter species, it lives in almost any suitable habitat. But where it issympatric with other otter species, it avoids smaller streams and canals in favour of larger water bodies.[2]Smooth-coated otter groups studied in theMoyar River preferred rocky areas near fast flowing river segments with loose sand and little vegetation cover.[11]
The population in theMesopotamian Marshes was feared to have perished, but otter tracks were found in 2009, suggesting the population may have survived.[12] Skins of smooth-coated otters were found during surveys between 2005 and 2012 in the vicinity ofHammar andHawizeh Marshes. Tracks and scat found inErbil Province were also thought to have been left by smooth-coated otters.[8]
InGujarat, smooth-coated otters were documented near lakes, canals andmangroves in the outskirts ofSurat in 2015.[13] In Singapore, smooth-coated otters have adapted well to urban environments, and have been observed to use urban structures like gaps under buildings as alternatives for holts. They also use staircases and ladders to get in and out of concrete canals with vertical or near‐vertical banks.[14]This population is well-protected and steadily increasing, with some families, such as theBishan otter family, becoming a common sight and attracting media attention.[15]
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The smooth-coated otter lives in groups of up to 11 individuals. They rest on sandy riverbanks and establish their dens under tree roots or among boulders. Observations inPeninsular Malaysia indicate that they are active foremostduring the day, with a short rest during midday. They mark their playground by urinating andsprainting on rocks or vegetation.[16][17]
They communicate through vocalisations such as whistles, chirps, and wails.[2]
Smooth-coated otters were observed to forage on river banks among tree trunks.[16]They feed mainly on fish includingTrichogaster,climbing gourami andcatfish. During the rice planting season, they also huntrats in rice fields. Snakes, amphibians and insects constitute a small portion of their diet.[18] Especially in areas where they share habitat with other otter species, they prefer larger fish, typically between 5 and 30 cm (2.0 and 11.8 in) in length.[10][19]
InKuala 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.[20]
Smooth-coated otters form small family groups of a mated pair with up to four offspring from previous seasons.[21]Copulation occurs in water and lasts less than one minute.[22]
As long as the food supply is sufficient, they breed throughout the year, but where they depend onmonsoon precipitation, they breed between October and February. The largest recorded wild-born litter of seven pups was observed in Singapore in November 2017.[23]Pups are born after agestation period of 60 to 63 days, with a usual litter size of up to five pups. The mothers give birth to and raise their young in a burrow near water. They either construct such a burrow themselves, or they take over an abandoned one. At birth, the pups are blind and helpless, but their eyes open after 10 days. They are weaned at about three to five months and reach adult size at about one year of age, andsexual maturity at two or three years.[2]
The smooth-coated otter is threatened bypoaching,loss and destruction of wetlands, as these are converted for settlements,agriculture andhydroelectric projects; water courses are beingpolluted bypesticides such aschlorinated hydrocarbons andorganophosphates. These factors lead to a reduced prey base. Otters are indiscriminately killed especially ataquaculture sites. Trapping of otters is prevalent in India, Nepal, and Bangladesh.[1]
Along theChambal River in India, smooth-coated otters are most vulnerable during winter when they rear young. During this season, they are disturbed by humans harvesting crops and removing wood along rocky stretches of the river.[24]
Six juvenile smooth-coated otters were discovered in a bag left atBangkok International Airport in January 2013. This was the first case of smooth-coated otters thought to have been destined for the illegalpet trade.[25]At least seven smooth-coated otters were offered for sale through websites by traders in Thailand and Malaysia between 2016 and 2017.[26]
The smooth-coated otter is a protected species in most range countries and listed globally as avulnerable species. It had been listed onCITES Appendix II since 1977.[1] Since August 2019, it is included inCITES Appendix I, thus strengthening its protection in regards to international trade.[27]
In southern Bangladesh, smooth-coated otters are used for commercial fishing. They are bred in captivity and trained to chase fish into fishing nets. By 2011, this fishing technique was used by about 300 fishermen, with an additional 2,000 people indirectly dependent on the technique for their livelihood.[28]
