Like sasquatch (aka "Bigfoot") and the Loch Ness Monster, that shaggy white biped known as the yeti ranks among the celebrity “cryptids,” rumored organisms lacking firm scientific documentation. A 2017 study examining samples purportedly from this mythic creature of the greater Himalaya put a major dent in the probability of its existence – and, at the same time, uncovered fascinating new information about the multiple kinds of bears roaming "yeti country."
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Researchers who conducted genetic analysis on purported yeti samples found all to derive from bears, save one that came from a dog. The study revealed new details about regional populations of brown and black bears, suggesting the intense terrain and Pleistocene glaciers resulted in a number of bear subspecies – Himalayan and Tibetan brown bears as well as Himalayan black bears – being isolated from one another.
The research, published in The Proceedings of the Royal Society B last fall, saw a team led by the University of Buffalo's Dr. Charlotte Lindqvist scrutinize a number of biological materials allegedly sourced from yetis – also called chemo, bharmando or, in the West, “Abominable Snowman.” The purported yeti bits – hair, skin, even feces – came from specimens collected by Icon Films, which solicited Lindqvist’s expertise for a 2016 documentary called Yeti or Not? Also providing samples to Lindqvist was the Messner Mountain Museum, founded by legendary Tyrolean mountaineer Reinhold Messner, who’s conducted his own investigations into the yeti myth.
Lindqvist, whose interests in genetics and speciation see her exploring such varied subjects as polar-bear evolution and marine-mammal gut microbes, didn’t really have Himalayan cryptids on her radar_. "I certainly don’t work on yetis generally, and never really thought I would," she told David Moscato of Earth Touch News._
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But the DNA analysis, which also encompassed bone, hair and scat collected from Himalayan/Tibetan Plateau brown and black bears, offered a unique opportunity to assess the genetics of the region’s under-sampled ursids. "I thought it could be a really interesting way to get a hold of samples of bears in the region if it really proved that these yeti samples actually turned out to be bears," Lindqvist told Moscato.
And that’s just what she and her colleagues found when analyzing DNA from the samples: clear genetic support for the notion – already widely held by many scientists, and what Messner concluded after more than a decade of research – that the yeti is a bear, not some mysterious species of primate.
One so-called yeti tooth from the Tibetan Plateau turned out to be a dog; all the other yeti samples yielded bear DNA.
Ironing Down the Bear Family Tree on the Roof of the World
Diehard yeti believers may despair at the results, but those results are great fodder for bear enthusiasts: shedding much-needed light on the shadowy taxonomy of the brown and black bears calling the Himalaya and Tibetan Plateau home.
Several varieties of the astonishingly wide-ranging brown bear have historically been described from Central Asia, including the Himalayan brown bear, often reddish in pelage, which grazes and munches on rodents above timberline; the Tibetan brown bear (or "blue bear"), commonly collared with white fur; and the desert-dwelling Gobi bear, called mazaalai in Mongolia. Similarly, the Asiatic black bear (a.k.a. moon bear) inhabits this part of the world as three regional subspecies: the Himalayan, Tibetan and Indochinese.
The 2017 study suggests that the topographic realities of the Himalaya – the world’s highest mountains – and the Tibetan Plateau – the world’s highest plateau, and among the geologically youngest – has, in concert with the advance and retreat of prehistoric glaciers, isolated these bear subspecies from ancestral populations and from each other.
Himalayan and Tibetan Brown Bears
The DNA analysis links the Gobi bear with the Himalayan brown bear, and concludes the subspecies represents a relict strain that diverged from other brown bears nearly 650,000 years ago and has been isolated by the Himalaya and other High Asia ranges ever since. Its split from the main brown-bear line took place during the Himalayan/Tibetan Plateau region’s most extensive bout of Pleistocene glaciation.
Tibetan brown bears, meanwhile, share a common ancestor with the Eurasian brown bear and the North American grizzly and likely diverged more recently: about 343,000 years ago. This happened during an “interglacial” period – an interval between active glacial advances – when, presumably, ancestral Eurasian brown bears colonized the bleak highlands of the Tibetan Plateau. Through geographic isolation from lower-elevation brown bears and then subsequent glacial advances, those Tibetan bears developed into their own subspecies.
The sublimely skyscraping crest of the Himalaya, meanwhile, keep the Himalayan and Tibetan brown bears – not terribly far apart in straight-line distance – from mingling. Himalayan brown bears inhabit the western Himalaya as well as scattered points northward, while Tibetan brown bears roam the range's southeastern flanks, plus of course the adjoining Tibetan Plateau.
Himalayan Black Bears
The team also determined that Himalayan black bears, which overlap in range with Himalayan and Tibetan brown bears but usually inhabit lower-elevation forests, represent a “sister lineage” of other Asiatic black bears, similar to the Himalayan brown bear’s status within its species. The DNA findings suggest it broke off from other black bears about 475,000 years ago – during the same interglacial period when Tibetan brown bears evolved.
While these findings may grab headlines for (maybe) disproving the Abominable Snowman, they’re most significant for adding valuable nuggets of knowledge to our as-yet sketchy understanding of brown and black bears in high-altitude Asia, which are under major threat from humankind: habitat loss, poaching and more. As the paper notes, the International Union for the Conservation of Nature (IUCN) classifies the Himalayan brown bear as Critically Endangered and the Asiatic black bear in general as Vulnerable; we know little, meanwhile, of the Tibetan brown bear’s population status. These unique forms of brown and black bear, inhabitants of the greatest high country in the world, are mighty special beasts themselves – yeti or not.