Gangetic Dolphins

+91

The first-ever estimate of Gangetic dolphins, the only riverine dolphins in India, has recorded 6,327 dolphins in the Ganga and its tributaries

The survey, conducted since 2021, covered 8,507 km across Uttar Pradesh, Bihar, West Bengal, and Assam.
Maximum number of dolphins were found in Uttar Pradesh, followed by Bihar, West Bengal, and Assam.
The study relied on acoustic hydrophones and triangulation methods for dolphin detection.
About Gangetic Dolphins:
o Common Names: Ganges river dolphin, blind dolphin, Ganges susu, Hihu, Bhagirath.
- Conservation Status: IUCN – Endangered, WPA - Schedule – I, CITES - Appendix - I
- - Distribution: Historically found in Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of India, Nepal, and Bangladesh.
  o Restricted to disjunct stretches in India’s Ganga-Brahmaputra-Barak river system, Nepal’s Karnali, Sapta Koshi, Narayani Rivers, and Bangladesh’s Meghna, Karnaphuli, Sangu rivers.
  
  o Recorded in mainstream Ganga River and tributaries like Ghaghra, Kosi, Gandak, Chambal, Rupnarayan, and Yamuna.
  - Characteristics, Habitat, and Behaviour:
  o Physical features: Long thin snout, rounded belly, stocky body, large flippers, and a slit-like blowhole.
  
  o Sexual dimorphism: Females larger than males; give birth once every 2-3 years to a single calf.
  
  o Coloration: Calves have chocolate brown skin at birth; adults have grey-brown, smooth skin.
  
  o Freshwater species, essentially blind, using ultrasonic sound waves (echolocation) to hunt.