This diversity is the result both of the size of the park’s grizzly population, and of the actual location of the park. Its 21,000 square km provide many corridors connecting bear populations from the Alaskan Panhandle, in the west, to the shores of Kluane Lake, on the northern boundary of the park. Solitary animals, individual grizzlies have an extensive home range (up to 1800 square km), going far afield to find food and mates across the region’s rugged mountainous terrain. (It’s been recorded that some male grizzlies travel up to 250 km, as the crow flies, every year.)

Grizzly bears are also a population that is increasingly facing an encroaching human presence into their natural habitat. Unlike other bears found in Canada, grizzlies require relatively undisturbed wilderness to call home. As a result, they have fared much worse than other species of bears, with the grizzly’s North American range now half of what it once was.

By monitoring the movement and health of grizzly bear populations, wardens are able to better understand these giants and how their continuing survival can be ensured.

The tracking of the grizzlies begins in the air, when Kluane Park staff head out in helicopters to spot the animals. Once they have seen a bear, the wardens, biologists, and others in the aircraft quickly estimate its weight in order to prepare the right amount of tranquillizer to sedate the animal (an adult male grizzly can weigh up to 400 kg, females half that). The medication is inserted into a dart, which is shot at the animal from the helicopter hovering above it. When the bear is fully sedated, the helicopter can land safely, and the data collection and fitting of tracking devices begin.

Park staff record basic information such as where the bear was spotted and tranquillized, how long it took to go down, how long it was handled – up to 30

minutes sometimes – and how long it took to revive. Once the dart is removed, various measurements are taken – the dimensions of the animal’s skull, the circumference of its neck, its shoulder height, and its length from nose to tail (when standing, an average full-grown male grizzly is about 2 m tall; some are even taller). In the course of their examination, the bear’s mouth is pried open to check its sharp, bone-crunching teeth. Often a vestigial molar tooth is pulled to estimate the bear’s age, and samples are taken of the grizzly’s hair and blood for recording DNA data.

Before the grizzly revives, park staff fit tracking devices onto the animal. There are three of these: an identifying ear tag and lip tattoo, and a radio collar. The collar contains either a small VHF (Very High Frequency) transmitter, which allows for tracking by fixed-winged aircraft; or a GPS (Geographic Positioning System) receiver and computer. The GPS device is a more