Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Subfamily: Lutrinae
Genus: Lutrogale
Species: perspicillata

Range and Habitat


Smooth coated otters live in southern and southeast Asia, India, China, Indonesia, with a small, isolated population in Iraq. They are found in a wide variety of habitats, from mangrove forests, forested wetlands and rivers, and peat swamps, to rice fields. They require undisturbed forest or dense scrub adjacent to the water. In their river habitat, they choose rocky rivers over smoother clay and sandy banks because the rocky river banks provide more cover and denning areas.


Physical Appearance


The smooth otter is the largest of the Asian otter species. They get their name from their fur, which is shorter and smoother than other otter species. Like all river otters, the smooth-coated has a thick, cylindrical, elongated body set on short, stocky legs. Their short, glossy, dense fur is a raw umber to smoky-grey brown, with a lighter colored underside, neck and chin. They have a soft, wooly undercoat, which is 6-8 mm in length, covered by coarse, shiny guard hairs, which are 12-14 mm in length. These guard hairs keep the undercoat dry when the animal is wet, keeping the animal warm and insulated. Unlike other aquatic mammals like seals, otters lack an insulating layer of body fat, so they rely solely on their fur to keep them warm and dry.

The thick tail is very long, and tapers from the base to the tip. The tail is unlike other otter tails in that it is more flattened, especially near the tip. The tail can be up to 60% of the total length.

Their head is rounded and flattened, with small, round ears set low on the head. Compared to the Eurasian otter, the smooth coated otter has a higher domed head, shorter muzzle, and more rounded head shape. Their muzzle is short and broad, and rounded in shape, and covered in thick whiskers. The thick neck is short, and is as wide as the head. They have small, round eyes that are set high and wide apart. Their nose is shaped like a stretched-out pentagon. The dental formula is: I 3/3 C 1/1 P 4/3 M 1/2 = 36.

The paws have thick, well-developed webbing that extends to the second joint of each digit. Their paws are large, with five toes on each foot equipped with strong but short claws. They have better dexterity than the Eurasian otter. Otter's front legs are shorter than their back legs, and this allows them to swim better. When otters swim slowly, they paddle with all four webbed paws. When swimming quickly or diving, the shorter front paws are kept close to the sides of the body, and the back legs and powerful tail propel then through the water. The ears and nostrils can be closed when they dive underwater. Both sexes have anal scent glands which are used to mark the boundaries of territories. Males are significantly larger than the females. Females have 2 pairs of mammae.



Diet


The smooth otter feeds on fish, crustaceans, frogs, water rats, turtles, and aquatic birds. Fisherman in India and Bangladesh train otters to herd fish into nets.


Reproduction and Life Cycle


Smooth otters, unlike most other otter species, form strong monogamous pairs. There is no set breeding season, and they can breed year-round, good weather and food supply permitting. The young are born in a den near the water's edge. The eyes open at 1 month, and they begin to swim at 2 months. They are weaned at 3-4 months, and will leave the family group at around 1 year of age, but will sometimes stay longer, forming a family group.


Social Behavior


Smooth otters are unusually social as river otters go. Males and females live and raise the young together. The female appears to be the dominant one, over all animals in the group. Territorial boundaries are marked with spraint and secretions from their anal glands. Home ranges are 7-12 sq km, and include one or more holts (den), that have at least one entrance below the water. They are active during the daytime and the night. They hunt as a family group using teamwork.


Threats


Though they are fairly common throughout their range, they are still threatened by pollution and habitat loss.


Subspecies


Lutrogale perspicillata maxwelli -- Iraq. May be extinct.
Lutrogale perspicillata perspicillata -- widespread subspecies.
Lutrogale perspicillata sindica -- Indus Valley in Pakistan. Smaller and paler in coloration.


Online References


Amblonyx.com: Smooth otter
Image Credit
Indian Wildlife: Smooth otter
IUCN Red List of Threatened Species - Lutrogale perspicillata
Otterjoy: Smooth Otter
Otternet: Smooth Otter
Sungei Buloh Wetlands Reserve: Smooth Otter