As a Peter Buck Postdoctoral Fellow in the Department of Vertebrate Zoology, I study the evolutionary relationships and distributions of mammals, and I am currently conducting research on deer species of North and South America. I’m interested in the methods used by scientists in identifying species. When my collaborator, Dr. Ronald Pine, a former curator at the National Museum of Natural History, mentioned some suspicious statements he found in a scientific report that claimed an unknown type of bear exists in the Himalayas and that it may be, at least in part, the source of yeti legends- I wanted to investigate!
Dr. Gutiérrez with skulls of bear specimens at the Division of Mammals. Photo by Molly McDonough.
The claim was published last year by B. Sykes and collaborators, in an article reporting results of a study that used DNA from hair samples that had been attributed to “anomalous primates” (yetis, bigfoots, and others). That study demonstrated that none of the samples had come from an “anomalous primate.” All but two samples were identified as well-known species of mammals, including one human; the two exceptions were said to have come from the Himalayas and to have, according to the study, DNA matching that recovered from a fossil Polar Bear from over 40,000 years ago.
Himalayas as pictured by NASA Landsat 7 Satellite, via Wikipedia.
Triggered by skepticism on the extraordinary claim that an unknown type of bear was lurking in the Himalayas, we felt that a closer look at the data and their interpretation needed to be made—after all, the evidence provided by Sykes and collaborators was from merely a tiny fragment of mitochondrial DNA. We reanalyzed the data and concluded that the relevant genetic variation in Brown Bears makes it impossible to assign, with certainty, the supposedly Himalayan samples to either that species or to the Polar Bear. Owing to genetic overlap, the samples could have come from either one. Because Brown Bears occur in the Himalayas, we found that there is no reason to believe that the samples in question came from anything other than ordinary Himalayan Brown Bears.
An illustration of a Brown Bear (Ursus arctos) from the highlands of Asia—the likely source of genetic material that has been attributed to an unknown species. Original drawing by Dutch zoological illustrator Joseph Smit (1836–1929), modified by entomologist and scientific illustrator Franziska Bauer.
As part of our study, published in the journal ZooKeys, we examined how the gene sequences analyzed might show how six present-day species of bears, including the Polar Bear and the Brown Bear; and the extinct Eurasian Cave Bear; might be related. Interestingly, we found that one sequence from an Asian Black Bear from Japan indicated that that bear was not closely related to members of that species, from the mainland. This unexpected large evolutionary distance between these two geographic groups of the Asian Black Bear probably deserves further study. A study looking at the genetic and morphological variability of Asian Black Bear populations throughout the geographic distribution of the species is yet to be conducted, and it would surely yield exciting results.
By Eliécer E. Gutiérrez, Peter Buck Postdoctoral Research Fellow, Division of Mammals, National Museum of Natural History