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.

In a visit to the Cornell Lab of Ornithology in upstate New York -- the premier institution for the study of birds, with a staff of 50 scientists and educators -- I was amazed by the range of new approaches there, especially the use of sound. The lab has developed software that identifies the noises many kinds of animals make, and offers that software to researchers around the world. The lab also has built a vast audio library, and anyone with Internet access can hear thousands of distinctive birdsongs and the various calls of mammals, amphibians, reptiles, fish and even arthropods. The study of birds began long before binoculars were available; pioneering ornithologist John James Audubon, in the early 19th century, had to shoot birds to study them up close. Today's technologies include arrays of microphones and radar installations to gather data as flocks of snow geese and migrating hummingbirds pass overhead.

At the University of Montana Flight Research Lab, I've watched researchers like Bret Tobalske use lasers and other tools to discover exactly how birds fly, and even to explore how their habitat shapes their physiology. In one experiment in the warehouse-like flight lab, while a Rolling Stones recording rocked out in the background, Tobalske placed a small hummingbird he had captured in his yard into a plexiglass cube. As the tiny bird hovered and drank from a feeding tube, an emerald green laser beam illuminated a fine cloud of olive oil hanging in the air. A camera recorded the movement of the swirling mist, detailing how lift, drag and other forces work on the bird as it flies. By understanding a bird's flying strategies, scientists can learn more about its ecology. The hairy woodpecker, for instance, has evolved a technique to get from one bug-infested tree to another as fast as possible using a minimal amount of energy, with a distinctive combination of flapping and gliding flight. "Flight is extraordinarily expensive per second (when it comes to energy use) and birds have evolved ways to sidestep some of those costs," Tobalske said. "It tells us something about (how they deal with) predator risks and why they feed where they do."

Meanwhile, isotopes -- stable compounds created primarily by the planet's geologic processes and then naturally dissolved in water -- are being interpreted in new ways to monitor wildlife. When clouds move across the landscape and drop rain, they leave hydrogen, carbon and deuterium and other isotopes in soil and vegetation in unique and varied ratios. So the isotopic fingerprint of, say, the Lamar Valley in Yellowstone National Park is different than that of the Pelican Valley, which is also in the park. When a bear or mountain lion drinks water from different sources, a record of those isotopes is formed in its hair or claws, and biologists can later analyze it to determine where the animal has been drinking. Researchers analyzing isotopes can also identify what portion of a bear's diet is meat, vegetation or fish. The technique does not require trapping the animal, but it does require gathering isotopic ratios across vast areas -- known as "isoscapes" -- to accurately compare an animal's tissue with the places on the landscape it has visited.

That technology has other uses: After a camper was attacked and killed by a grizzly near Yellowstone in 2010, for instance, biologists killed the bear and tested a snip of its hair for a corn isotope. Since almost every processed food contains corn syrup, they could discover if the bear in question had been corrupted by human garbage. In this case, it hadn't.