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Platanista gangetica gangetica

2022-09-04 08:57:56 166

Platanista gangetica gangetica Life habits and morphological characteristics

Adult Gangetic river dolphins weigh 51-90 kg and are 200-400 cm long. Females are larger than males. The skull is highly asymmetrical, tilted to the left, with a steep forehead and longitudinal ridges on the jaw. These river dolphins are unique in their long necks and immature vertebrae. This allows them to be extremely flexible from head to tail. The dorsal fin has a triangular ridge with a sharp tip. The forelimbs and tail fin are relatively large compared to the body. The tail fin is soft.
The color of the male and female body varies greatly, ranging from light blue, gray with different shades, to dark brown. The color of the abdomen is lighter than the back and sides, and the middle part of the body is brown.

Platanista gangetica gangetica Distribution range and habitat

Distributed in Bangladesh, India, Nepal, Ganges River Basin, Ganges-Brahmaputra Basin and Karnaphuli-Sangu river basin.
Gangetic river dolphins inhabit freshwater river systems in South Asia. Habitats include tropical freshwater lakes, ponds, rivers and coastal brackish waters. Lives in the Ganges and Indus river systems and their many tributaries, streams and connecting lakes. Distributed in the hills and lowlands of Nepal (approximately 250 meters above sea level), sometimes in tributaries in flood plains and areas of high-flowing rivers. These river dolphins prefer areas that create eddy countercurrents, such as small islands, river bends and converging tributaries. Since these animals occupy a wide range of river systems, they can tolerate a wide range of temperature differences, ranging from 8-33 degrees Celsius. Altitudes range from 0-250 meters, water depths range from 3-9 meters, and leap into the air every few minutes. During the monsoon season, dolphins in the Gangetic bas

Platanista gangetica gangetica Detailed Introduction

The Ganges River Dolphin is a nominative subspecies of the South Asian river dolphin.

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The Ganges River Dolphin looks like a crocodile. When breathing, it often floats to the surface at a certain angle, so it may be mistaken for a crocodile in some areas. The entire head and beak of the Ganges River dolphin can be seen when swimming, and sometimes only the forehead or the upper half of the head and the beak float on the water. The pectoral fins of the Ganges River dolphin are in shallow water. It usually leans to the right and cruises near the bottom of the river; the tail is slightly higher than the head (the head will keep nodding); the other pectoral fin is usually dragged in the mud to search for food. The dorsal fin is located in the center of the body and slightly behind the body.

According to reports, Ganges River dolphins swim sideways more often at night; late at night is the peak period for sideways swimming. It also often swims in circles in the water, and usually in a counterclockwise direction. The tail fin functions like a paddle, with a protruding bone ridge. The right pectoral fin will drag in the mud. It often swims to the shallow water near the shore to hunt at dawn and dusk. It usually swallows freshwater fish less than 6.5 cm in length as a whole, and also eats a small amount of aquatic plants and insects. The vision is almost zero, and it relies on echolocation to understand the changes in the environment.

The Ganges River Dolphin feeds mainly on fish and shrimp, including carp and catfish. When observed, the Ganges River Dolphin usually moves alone or in loose groups, and they do not form strict and obvious groups with interaction.

The Ganges River Dolphin can breed throughout the year, but it is concentrated from October to May. The juvenile dolphin weighs about 7.5 kg at birth, is weaned after about a year, and reaches sexual maturity at the age of 10. There is no more information about the mating of the Ganges River Dolphin.

The Ganges River Dolphin is one of the endangered animals. Industrial, agricultural and human pollution is a serious cause of habitat degradation. 9,000 tons of pesticides and 6 million tons of fertilizers are used near the river every year. High levels of pollution can directly kill dolphins' food and the dolphins themselves, completely destroying their habitat. As a top predator, river dolphins are known to have high levels of persistent toxic chemicals in their bodies, which may have adverse effects on their health. In addition, because humans use fishing nets in their lives, they can get entangled, and agricultural irrigation also reduces the water level of rivers within the habitat of Gangetic river dolphins. Many dams built for hydroelectric power have seriously affected their movement and distribution areas, and many populations have been dispersed and confined to isolated small areas. Elsewhere in the Gangetic Mountains, four existing subpopulations are isolated by dams. In the Damodar River system, at least ten dams and barrages built in its main stem and tributaries may further seriously affect the dolphin habitat downstream, reducing and dispersing the dolphins' ability to survive. Habitat fragmentation has a significant impact on the survival and reproduction of Gangetic river dolphins. In 1982, the total number of Gangetic dolphins was estimated to be 4,000-5,000, less than 2,000 in 1997, and about 1,200-1,800 in 2001.

Listed in the 2012 Red List of Endangered Species of the World Conservation Union (IUCN) ver 3.1 - Endangered (EN).

Listed in the first level of the "List of National Key Protected Wildlife in China".


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