The Japanese giant salamander, a rare amphibian often called a "living fossil," could disappear as a distinct species as interbreeding with its Chinese relative increases.

Over the years, Japanese and Chinese giant salamander hybrids have proliferated in western Japan, triggering alarm bells and a flurry of activity to preserve the native species.

The Japanese giant salamander, which at up to 1.5 meters long is the world's second-largest amphibian after its Chinese relative, inhabits rivers and streams in the Chugoku, Kinki and Chubu regions.