Ganges river dolphin, blind dolphin, Ganges dolphin, Ganges susu, Gangetic dolphin, hihu, side-swimming dolphin, South Asian River Dolphin

Kingdom : Animalia, Phylum : Chordata, Class : Mammalia, Order : Cetartiodactyla, Family : Platanistidae, Genus : Platanista, Species : gangetica

IUCN : Endangered, IWPA : Schedule I, CITES :Appendix I, U.S ESA : Endangered

Two subspecies (P. gangetica gangetica and P. g. minor) occur in the Indus, Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of the South Asian subcontinent, from the deltas upstream till they are blocked by rocky barriers, shallow water, fast currents, dams or barrages (low, gated diversion dams). The three river systems are disjunct and, therefore, have their respective dolphin subpopulations. However, there may be an occasional demographic interaction between the latter two during the high-water season if the freshwater plumes of the two systems meet. There is further subpopulation separation within all three systems, much of it caused by physical barriers constructed within the last 100 years.

A long thin snout, rounded belly, stocky body and large flippers are characteristics of the Ganges river dolphin. The species has a slit similar to a blowhole on top of its head, which acts as a nostril. Females are larger than males and give birth once every two to three years to only one calf. The calves have chocolate brown skin at birth, while the adults have grey-brown smooth, hairless skin. The Ganges river dolphins can only live in freshwater and are essentially blind. They hunt by emitting ultrasonic sounds waves that bounce off of fish and other prey. They are frequently found alone or in small groups; generally, a mother and calf travel together. The dolphin has the peculiarity of swimming on one side so that its flipper trails the muddy bottom. It is understood that this behaviour aids them in finding food. Being a mammal, the Ganges river dolphin cannot breathe in water and must surface every 30-120 seconds. Because of the sound it produces when breathing, the animal is popularly referred to as 'Susu'. Although not well studied, the movement of the Ganges river dolphin follows seasonal patterns. It is observed that animals travel upstream when the water level rises, and from there enter smaller streams.

1. Unintentional killing through entanglement in fishing gear. 2. Poaching for dolphin oil, used as fish attractant and for medicinal purposes. 3. Habitat destruction due to development projects (e.g. water extraction and the construction of barrages, high dams and embankments), pollution (industrial waste and pesticides, municipal sewage discharge and noise from vessel traffic) and overexploitation of prey mainly due to the widespread use of non-selective fishing gear. 4. Fragmented populations created by dams and barrages have degraded downstream habitat and created impoundments with high sedimentation and altered assemblages of fish and invertebrate species.

Smooth-coated otters are relatively larger than other species, weighing from 7 to 11 kg (15 to 24 lb) and 59 to 64 cm (23 to 25 inches) in head-body length, with a tail 37 to 43 cm (15 to 17 inches) long. They may be distinguished from other species of otters 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, which with shorter front legs makes swimming smooth and easy. The fur is thick and velvety with two layers; the guard fur keeps the underfur dry underwater to retain body heat. Males are larger than females. Otters prefer rocky stretches 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. Smooth-coated otters are social and hunt in groups and are mainly diurnal, and have a short lull in activity during midday.

1. Loss of wetland habitats due to construction of large-scale hydroelectric projects, reclamation of wetlands for settlements and agriculture. 2. Lack of adequate prey base for sustaining otter populations. 3. Polluted wetlands and waterways by eutrophication and accumulation of persistent pesticides such as chlorinated hydrocarbons and organophosphates through agricultural runoffs. 4. Polluted wetlands and waterways by eutrophication and accumulation of persistent pesticides such as chlorinated hydrocarbons and organophosphates through agricultural runoffs. 5. Poaching for pelt.

The Asian small-clawed otters occur in freshwater and peat swamp forests, rice fields, lakes, streams, reservoirs, canals, mangrove and along the coast (Sivasothi and Nor, 1994). In the Western Ghats, they are mostly found along the hill streams. They were once common in the mangroves of east Calcutta and Sunderbans.

The Asian small-clawed otter has a flattened head and a short, thick neck; eyes are located toward the front of the head. The ears are small and rounded and have a valve-like structure. Nose pads are dusky or pinkish in color. The body is slender, streamlined and serpentine, and is flexible enough to allow grooming of all body. Dark, grayish-brown fur covers most of the dorsal surface with a lighter cream colouration on the ventral surface, especially on the face and neck. The fur has relatively short, fine, dense and velvety hair (less than 2.5 cm). The Asian small-clawed otters are diurnal animals (active during the day), found in remote areas, free of human disturbance. However, some have adapted to life near villages. They continually groom their fur to maintain its insulating qualities.

1. Habitat destruction due to changing land use patterns such as increased human settlements, deforestation, etc. 2. Poaching for pelt. 3. Reduction in prey biomass due to over-exploitation, which makes its remaining habitats unsustainable.

The Eurasian otter has one of the widest distributions of all palaearctic mammals. Its range covers parts of three continents: Europe, Asia and Africa. In India, it occurs in northern, northeast and southern India. Formerly widely distributed in Japan, it is now believed to be extinct there.

The Eurasian otter has sleek brown fur, which is often paler on the underside and a long lithe body with a thick tail and short legs. Adaptations for an aquatic lifestyle include webbed feet, the ability to close the small ears and the nose when under water, and very dense, short fur that traps a layer of air to insulate the animal. Many sensitive hair ('vibrissae') frame the snout; these help the otter to locate prey. Vocalizations include a high-pitched whistle between a mother and her cubs, twittering noises produced during play-fighting and cat-like noises when fighting. The Eurasian otter lives in a wide variety of aquatic habitats, including highland and lowland lakes, rivers, streams, marshes, swamp forests and coastal areas independent of their size, origin or latitude (Mason and Macdonald, 1986). In the Indian sub-continent, Eurasian otters occur in cold hill and mountain streams. During summer (April - June) in the Himalayas, they may ascend up to 3,660 m.

1. Habitat destruction due to developmental activities such as canalization of rivers, removal of bank side vegetation, dam construction, draining of wetlands and aquaculture activities. 2. Decrease in prey species due to acidification of rivers and lakes. 3. Poaching for pelt. 4. Coastal populations are vulnerable to oil spills, while the inland populations are vulnerable to organic pollution by nitrate fertilizers, untreated sewage, or farm slurry. 5. A potential risk comes from traps designed to kill other species, especially underwater cages constructed to drown muskrats.