Brave New Wildlife Biology: Grizzly Bear Soup
Part 2: Using tech—and cunning—to plot bears' family trees
Editor's Note: This is the second part of a four-part story on how new technologies—gene sequencing, GPS tracking, remote monitoring and the like—are revolutionizing wildlife biology for better and, in some ways, for worse. Click here for Part 1, here for Part 3 and here for Part 4.
Kate Kendall, a research ecologist with the U.S. Geological Survey, based in West Glacier, Montana, has created her own special recipe for grizzly bear soup: She dumps assorted carp, trout and other fish into a 55-gallon drum, and stirs in cattle blood gathered from slaughterhouses. Then she seals the fetid concoction and lets it age for a year, until it's good and ripe. "Then we open the drums and bottle it," she told me recently.
Last summer, Kendall and 75 others on her crew wrapped barbed wire around stands of pine trees at 395 locations in northwestern Montana's two-and-a-quarter-million-acre Cabinet-Yaak Ecosystem, to create what she calls "hair corrals." In the center of each corral, the team placed a generous dollop of Kendall's homemade lure on a pile of brush and stumps.
Remote cameras show that after the team left each corral, it seldom took long for the scent to work its magic. As the bears sneak under the wire to check out the heavenly smell, the barbs snag clumps of their hair. That project snagged 17,000 hair samples in that ecosystem. Once black bear hair is excluded from the samples, the DNA—the basic genetic material—in each grizzly hair will be assayed. In 2014, for the first time ever, the local people will have a realistic idea of how many grizzly bears live in the Cabinet-Yaak ecosystem, where they go and even their kinship: which bears are related to others and in what ways. That will give bear managers a much better sense of how many animals they are dealing with, compared to previous estimates based on radio collars and sightings. Moreover, the bears will never see a human being, never be drugged, and probably never know they have been studied.
A similar project led by Kendall in the Northern Continental Divide Ecosystem revealed a dramatic finding by the time it ended in 2008. Biologists had estimated that 300 grizzlies lived in that ecosystem, but the DNA results indicated more than twice that: 765, all told. "That's a totally different story," Kendall said. "Population numbers and trends are critical (for determining) if conservation methods are effective."
DNA analysis is revolutionizing wildlife research in many ways. It allows researchers to easily collect data on more than one animal, for instance. The old method—live trapping—allows researchers to sample blood and tissue from just a few bears. But collecting DNA in scat or hair allows them to gather information on two or three dozen, or even two or three hundred. They can calculate not only basic population numbers, but—as Kendall has done—relationships. Servheen's agency has assembled a complete family tree of all the grizzly bears between the Yukon and Yellowstone. In one example of how that's useful, when a grizzly was killed in the Selway-Bitterroot in 2007, DNA revealed that it had come from the Selkirk Mountains in northern Idaho—an indication of a migration corridor that needs to be preserved.
"The genetic code is a mystery novel, a history book and a time log in a single hair," Michael Schwartz, a research ecologist at the U.S. Forest Service Rocky Mountain Research Station in Missoula, observed recently. "We are answering questions we couldn't even ask a few years ago." He described a potential breakthrough regarding pneumonia in bighorn sheep, which often catch it from domestic sheep; the domestic sheep are merely carriers, but the disease is often fatal to bighorns. Agricultural researchers know which genes govern disease resistance in domestic sheep, and now biologists can sequence the bighorns' genes and try to determine if some bighorns have a similar genetic resistance. "The gene for resistance may have drifted out of (a bighorn) population through random processes," Schwartz said, "so we know we need to bring in these genes" from other herds.
In Portugal, DNA researchers lined the back wall of a lynx den with cork, and placed a parasitic Amazonian kissing bug in a quarter-sized hole covered with a thin plastic membrane. When the lynx entered the den, the bug drilled through the plastic, bit the lynx and sucked its blood. After the cat left, they recaptured the bug and examined the blood and DNA it contained. Researchers in Vietnam who analyzed the blood from 25 leeches found genetic material from three mammal species that were rare and not well understood, including two that were only recently discovered—a deer called the Truong Son muntjac and the Annamite striped rabbit.
This story first appeared in High Country News.