The Ganges River Dolphin is one of the world's most endangered freshwater mammals.
Its numbers in South Asia have plummeted in recent decades. But Indian conservationists working on the Brahmaputra River hope to reverse the dolphin's decline by mobilising riverside communities to protect these amazing cetaceans.
"We named one dolphin Rosie. I think Rosie is arriving here," said conservationist biologist Abdul Wakid, pointing to rippled brown water where Rosie had just surfaced, "She's really big."
You have to be quick to see a Ganges River Dolphin. The sliver of back and tiny dorsal fin slipped beneath the surface within a second. At about 2.5m, Rosie is about as long as this species of freshwater dolphin grows.
Despite her name, she's black in colour - distinct from the Pink River Dolphin of the Amazon River system.