The Ganges river dolphin (scientific name: Platanista gangetica) is a nominated subspecies of the South Asian river dolphin. This precious freshwater dolphin is mainly distributed in Bangladesh, India, Nepal, the Ganges River Basin, the Ganges-Brahmaputra River Basin, and the Karnaphuli-Sangu River Basin. What is the fate of this dolphin in the Ganges, one of the most polluted rivers in the world?
Ganges river dolphins have very small eyes, no lenses, and are effectively blind, but they can sense the intensity and direction of light. They navigate and forage with echolocation and can determine the size, distance, direction, and density of prey. Ganges river dolphins usually travel alone or in loose groups and do not form tight groups with obvious interactions. They mainly eat fish and shrimp, including carp and catfish.
Generally, the eyesight of freshwater dolphins is weak, which is related to their long-term living in turbid river environments. Rivers are usually very turbid after rains and floods, plus human pollution. For dolphins, having eyes underwater is superfluous. The Ganges river dolphin is one of the endangered species, with industrial, agricultural, and human pollution a serious cause of habitat degradation. The following post shares more interesting facts about this endangered species.
Ganges River Dolphin Size and Appearance
The most notable feature of the Ganges dolphin is its asymmetrical skull, which is often sloped to the left, with a steep forehead. These freshwater dolphins are unique in their long cervical vertebrae and immature vertebrae. It allows them great flexibility from start to finish. Compared with the body, the forelimbs and caudal fin are larger, and the caudal fin is soft, accounting for about a quarter of the overall length. Unlike other dolphins, the Ganges lack nasal hairs.
They have the long beak common to all puffer fish, sometimes as long as 1/5 of their body length. The teeth at the end of the beak are longer and can be seen even when the mouth is closed. The body color of male and female Ganges river dolphins is quite different, and the body color ranges from light blue and gray with different levels to dark brown. The color of the abdomen is lighter than that of the back and sides, and the middle part of the body is brown.
Average Size of Ganges River Dolphin
Adult Ganges river dolphins weigh 50-90 kilograms and have a body length of 2-4 meters. Female dolphins are larger than male dolphins. Adults can reproduce throughout the year but are concentrated in October-May. Young dolphins weigh about 7.5 kilograms at birth, are weaned after about a year, and reach sexual maturity at about ten years old. The oldest known Ganges river dolphin was a 30 year old male.
|up to 30 years
Habitat and Life Habits
Ganges river dolphins inhabit freshwater river systems in South Asia, primarily the Ganges and Indus systems and their many tributaries, streams, and connecting lakes. These pufferfish like to create eddies in areas of countercurrent, such as small islands, river bends, and confluent tributaries. Because these animals occupy extensive river systems, they can tolerate wide temperature variations, ranging from 8-33 degrees Celsius.
Ganga river dolphins often surface at an angle while breathing, so they can be mistaken for crocodiles in some areas. The head and beak of the Ganges dolphin can be seen while swimming. According to the report, late at night is the peak time for side swimming of the Ganges river dolphins. They often swim to the shallow water on the shore to hunt for food in the morning and dusk. They usually eat freshwater fish, aquatic plants, and insects.
Both the Indian river dolphin and the Ganges river dolphin are considered living fossils because they are the oldest surviving species of dolphin. However, the Ganges river dolphin is listed on the IUCN Red List as endangered wildlife. Habitat loss due to water pollution is a serious reason for the dramatic decline of this species. Water pollution from high levels of persistent toxic chemicals can directly kill a dolphin's food and itself, destroying its habitat. Other threats these dolphins face include: straying into fishing nets, dikes, and bridges, restricting their range and mobility, collisions with boats, and poaching. Habitat fragmentation has had an important impact on the survival and reproduction of the Ganges river dolphin.