INCREDIBLE STORIES

"Royal Wool" of the Tibetan Antelope

The Forensics Lab, like any other crime lab, deals with many cases that we consider routine.  For our analysts, identifying elk meat by its DNA, or a golden eagle feather by its appearance, or lifting a fingerprint from a gunstock, are all in a day’s work.  But every year or two, we also face entirely novel challenges that require us to develop new techniques or new clues for species identification.  One such challenge involved the exotic fabric called “shahtoosh.”

The hair of the Tibetan Antelope is so fine that a shawl of this fabric can be pulled through a man’s ring; thus, they are sometimes called “ring shawls.” Credit: USFWS

Shahtoosh is woven from the warm, dense underfur of the Tibetan antelope, or chiru (Pantholops hodgsonii).  This graceful antelope inhabits one of the most forbidding environments on earth, the high, wind-swept Tibetan plateau.  In the bitterly cold winters, chiru grow a wooly coat, which is shed in the spring.  For generations, Himalayan weavers have gathered clumps of this shed wool — the finest produced by any mammal — and woven it into incredibly light-weight fabric shawls that were reserved for the use of royalty.  Thus, the fabric was called shahtoosh, which means “royal wool.”  Protected by the remoteness of their range, and by their speed and sharp eyes, Tibetan antelope populations were safe from human threats.

The Tibetan Antelope is protected by both the U.S. Endangered Species Act and at the highest level by the Convention on International Trade in Endangered Species (CITES). Credit: USFWS

All that changed with the Chinese occupation of Tibet, which brought roads and Kalashnikov rifles into the range of the chiru.  Suddenly, whole herds could be run down with vehicles and slaughtered.  Renowned conservationist George Schaller discovered that Tibetan antelope populations were crashing, and brought world attention to the connection between trade in shahtoosh and the plight of this unique species.  The Tibetan antelope is now listed on the U.S. Endangered Species Act (ESA) and protected at the highest level by the Convention on International Trade in Endangered Species (CITES).  All international trade in shahtoosh is prohibited. Tibetan antelope cannot be kept alive in captivity, and so the fabric comes only from animals which have been killed.  Nevertheless, demand for this luxury fabric remains high, with shahtoosh shawls commanding prices of thousands of dollars apiece.

To enforce the ban on shahtoosh, it is of course necessary to be able to identify the fabric.  When wildlife law enforcement seized shipments of shahtoosh shawls, these were invariably claimed to be “pashmina” or “shahmina,” legal fabrics woven from the wool of cashmere goats, often blended with silk.  Microscopic comparisons of the fine underfur of the Tibetan antelope and the cashmere goat unfortunately revealed no clear diagnostic differences.  The antelope hairs were slightly finer, but this difference was too subtle to be useful in the law enforcement context.

Microscopic examination of the Tibetan antelope guard hair shows a shaft filled with large, rounded cells. Credit: USFWS

At this point, Lab mammalogist and hair identification expert Bonnie Yates had an inspiration.  What about the appearance of the outer “guard hairs,” she wondered.  Since the fabric itself is woven from the underfur, the guard hairs from the animal’s outer coat were considered to be an undesirable contaminant and were typically ignored by fabric experts.   With her biological perspective, Bonnie reasoned that these large guard hairs – always present in small amounts in any wool fabric – might reveal species-diagnostic characters missing in the finer underfur.  Microscopic examination quickly proved her hunch to be correct.  The shafts of Tibetan antelope guard hairs were completely filled with large, rounded cells.  The shaft thus had the appearance of a clear tube filled with tightly-packed pebbles.  The shaft of a cashmere goat guard hair, in contrast, was much smaller in diameter and had a dark, solid-appearing core which did not fill the shaft.

Lab mammalogist and hair identification expert Bonnie Yates discovered how to scientifically identify the Tibetan antelope hair. Credit: USFWS

Using these characters, Bonnie was able to prove that suspect shawls indeed contained the wool of the endangered Tibetan antelope, leading to successful prosecution of shahtoosh cases in the U.S., England, and Asia.  Bonnie herself has traveled to Thailand to assist the Royal Thai Police in a major shahtoosh case, and to testify at a trial in Hong Kong where over a million dollars worth of shahtoosh shawls had been seized.

This is just one example of how Forensics Lab scientists combine their biological insight with laboratory techniques to expand the frontiers of wildlife forensics.

For detailed information on identifying shahtoosh shawls, please see the Lab publication Identification Guidelines for Shahtoosh and Pashmina (PDF 3,377 KB).

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