Population Studies

A lone polar bear on the sea ice.
Photo copyright Daniel J. Cox/Natural Exposures.

It's cold. It's difficult. It's dangerous. And you won't find the job on craigslist—but what a thrill to work with wild polar bears. Scientists say that the first polar bear of the season still takes their breath away, even after decades of working in the Arctic.

Why take population counts? They help scientists understand how the bears are faring. Long-term studies are especially important for understanding trends and for raising alarm bells as necessary.

Data from the Southern Beaufort Sea population, for example, helped lead to the U.S. decision to list the polar bear as a threatened species. The scientists collect data on:

  • Size and health of the population
  • Number of bears in each age and sex class
  • Movement patterns of the bears and how they're responding to declining sea ice

Satellite Collars

Scientists in the field place satellite collars on a select number of bears every spring. The technology lets research teams follow polar bears across the Arctic from the comfort of a warm office hundreds of miles away. Especially in winter, we have no other practical means of learning about polar bears during 24 hours of darkness, when arctic blizzards howl and temperatures plunge. 

The collars allow scientists to:

  • Track movements and habitat use
  • Determine hunting patterns
  • Measure the total distance traveled
  • Map home range areas
  • Collect data on cub survival rates

The collars are designed to fall off on their own in 14 months. Interesting fact:only female bears can wear collars. A male polar bear's neck is as wide as its head, so the collar just slips off!

You can follow some of the satellite-collared polar bears on our Bear Tracker Map

New Technology

Tracking technology continues to improve, so scientists are developing a new collar design as well as alternative tracking methods. These include smaller ear- and glue-on satellite tags. The non-collar tags don't deliver as much data—but they will allow scientists to track adult males and subadult bears, which will add to our understanding of polar bear ecology. Another innovation in the works is a "Burr on Fur" design being developed in partnership with 3M. It will allow scientists to attach a small tracking device to a polar bear's fur.

Aerial Surveys

Many parts of the Arctic are so remote that scientists can only make rough estimates about how many polar bears are there. In fact, of the 19 polar bear populations, 11 are classified as data-deficient.

Polar Bears International helped fund studies to refine techniques for taking accurate population counts by air. Aerial surveys would be far less expensive and time-consuming than traditional capture-recapture methods. Although capture efforts give us more detailed information on a population's health and movement patterns, aerial surveys will allow us to take a quick snapshot of how many bears there are in populations that we know little about.

Current Population Projects

Southern Hudson Bay Research

This collaborative study is gathering additional information on polar bears from the southernmost part of the Southern Hudson Bay population in James Bay. It follows on earlier work that suggests these bears may be somewhat genetically distinct from other SH bears—and might, therefore, merit consideration as a separate management unit. The study is identifying their movement patterns, including selection of maternity denning sites and will contribute to our knowledge of the broader Hudson Bay meta-population and system.

Western Hudson Bay Coastal Surveys

The sea ice in Hudson Bay melts completely each summer, forcing the bears onto land, where they undergo a prolonged fast. Polar bears in the Western Hudson Bay population gather along the coast in the fall as they wait for the ice to return. This provides an opportunity to test whether a simple aerial survey conducted could provide a valid index of population trends, including body condition and survival rates. Eventually, such coastal surveys may provide an important tool in monitoring remote polar bear populations range-wide.

PBI thanks the SeaWorld & Busch Gardens Conservation Fund for major funding on Western Hudson Bay.