Feared extinct in its highlands habitat, the singing dog—whose name comes from its coyote-like howls—was last photographed in the wild 23 years ago.

At least 200 captive singing dogs live in zoos and as pets around the world, descendants of a few wild dogs captured in the 1950s. But the animals—which resemble a domestic dog breed called the Shiba Inu—are severely inbred due to a lack of new genes.

In September, members of an Adventure Alternative Borneo tour group hiking the remote Mandala Mountain in West Papua, Indonesia (map), were surprised to see a tawny, thick-coated dog staring at them from a hillside.

"We watched it for around 15 minutes as it continued to watch us. It seemed