EPOW - Ecology Picture of the Week

Rare River Dolphin on the Brink

Ganges River Dolphin (Platanista gangetica), Family Platanistidae
Brahmaputra River, Assam, India

Explanation:  Look quickly!  This is the rare and highly endangered Ganges River dolphin, surfacing for just the briefest of moments for a fast gulp of air before vanishing again beneath the swirling currents of the Brahmaputra River of northeastern India.  
  

Ganges River dolphins are found at this spot, likely
because of the swirling eddies of muddy water in which
it can feed and swim without continually fighting the strong
river currents out in the main channel.
 

I stood on the banks of the river for a good half hour, here in Assam along Kaziranga National Park, waiting for it to surface between 5-10 minutes of submersion.  It was probably feeding along the bottom, as they do, swimming sideways and using echolocation in search of fish, invertebrates, and other prey.  Lacking a crystalline eye lens renders this cetacean essentially blind; it likely does not need sight as it feeds and occurs in the murkiest of river waters.
  

Here, the Brahmaputra River divides into many channels
with endless numbers of sand bars and shifting islands.
 

Caught twice here in the act of breaking the water surface, Ganges River dolphins rarely breach like oceanic dolphins, and usually barely break the water surface to breath.  I have seen them elsewhere along the Brahmaputra River in Guwahati, Assam's capitol city, where they barely made a ripple when surfacing.  
  

This time I caught the dolphin breaking the surface with its tail flukes,
as it sounded again after an instant's quick breath. 
 

Ganges River dolphins are entirely fresh water inhabitants and are highly endangered with only a few thousand remaining in the Ganges and Brahmaputra Rivers mostly in India and Bangladesh.  They are threatened with pollution, poaching, becoming entangled in fishing nets, and their habitat being altered by dams and other uses.

A placid scene of the Brahmaputra River's habitat for the
Ganged River dolphin belies the threats that this
terribly imperiled and wondrous animal is facing.