Smiling at danger

China's finless porpoises face a fight for survival in and around the Yangtze River but researchers see signs of hope, Kelly Wang reports in Wuhan.

In an oxbow lake along the middle reaches of the Yangtze River, a breathy sigh pierces the surface stillness as one of China's most endangered animals comes up for a gulp of hazy air.

A slick black back with no dorsal fin arches briefly above the water line before plunging back down.