Only eight bear species are known to science: The American Black Bear; The Brown Bear (grizzlies included); The Polar Bear; The South American Spectacled Bear; The Asian Sun Bear, The Moon Bear, and The Sloth Bear; and The Chinese Panda Bear. The moon bears’ lineage (most similar to that of the American black bear) as black-coated mountain dwellers had never been challenged; until author Sy Montgomery and her scientific colleagues turned up a new golden form.
In Montgomery’s 2002 book, Search for the Golden Moon Bear, she travels to the home of the moon bear in Southeast Asia, to track down what she hopes might be a new species of bear. What she finds is less than hopeful; bears kept in cages, often starving and neglected, their paws a culinary delicacy, their organs used for medicine. Yet Montgomery creates a hopeful narrative that weaves folklore, natural history, and scientific research into an evocative journey. Sy Montgomery is, according to Book Magazine, “A modern miracle. Bawdy, brave, inventive, prophetic, hell bent on loving this planet.”
The moon bear is a recognized species of bear that is native to Asia, also known as the Asiatic black bear. Scientists think that the moon bear is only distantly related to the American black bear (which is itself a close relative of the grizzly bear).
The Golden Moon Bear is something else. It might be a mere color phase of the regular moon bear, it might be a subspecies, or it might be a new species of bear altogether. The evidence gathered so far is not yet conclusive.
In the past, scientists were often fooled by color phases into declaring a new species or subspecies. Later, they would often discover animals of both color phases in the same litter, or they would find that color phases in that animal weren't tied to geographical regions.
In order to qualify as a different subspecies, the animals of a certain type need to both look different from the main species and have a distinct population living in an area or habitat that does not wholly overlap the range of the rest of the species. The Siberian Tiger is a good example of a subspecies. It looks different from other tigers, it is much bigger than them and better adapted to the cold. Along the southern part of its range it once blended gradually into the general population of Chinese tigers, yet even in those times it certainly had lands and a habitat type all to itself.
In order to qualify as a different species altogether, the Golden Moon Bear would need to meet more stringent requirements than those for a subspecies. Historically, scientists separated different species according to whether they could breed and produce fertile offspring. If they could, they were the same species, if not, they were different species. Today, that requirement has been dropped because there are too many wild animals that are obviously different species, yet produce fertile hybrids.
Lion and tigers produce fertile "ligers" in captivity, even though the two species probably never breed in the wild, are adapted to different habitats, and have different inborn social systems and instinctual habits. In the case of bears, it is now known that polar bears, American grizzlies, American black bears and European brown bears can all produce fertile offspring with one another. Because of these reasons, we would need to do a lot more research than merely breeding a Golden Moon Bear with a normal moon bear and seeing if fertile offspring were produced before we could decide whether it was a separate species or not.