Polar Bears International

Maternal Den Studies

Our maternal den study projects include:

  • A long-term study in Northern Alaska, started in 2011 with Dr. Tom Smith of Brigham Young University
  • A second, ongoing project in Svalbard, Norway, started in 2016 in partnership with the Norwegian Polar Institute and San Diego Zoo Global.

Both study the behavior of polar bear mothers and cubs as they emerge from their dens. Join them in the field through our Research Section.

Maternal Dens

As the Arctic melts, more polar bear mothers are choosing to den on land. In late fall, pregnant females tunnel into coastal snow banks to claw out dens where they give birth to their cubs. Snow soon drifts across the entry holes, completely hiding the dens from view.

Unfortunately, many of the best coastal denning spots buzz with industrial activity, yet little is known about polar bear denning behaviors.

A PBI team led by Dr. Tom Smith of Brigham Young University, who serves on our Scientific Advisory Council, spends weeks in the bitter cold of Alaska's North Slope every year, trying to find out:

  • When do polar bears typically emerge from their dens with cubs?
  • How long do families hang around at the den site before heading to the sea ice to hunt seals?
  • How sensitive to disturbances are denning polar bears?

This research give us a broader picture of denning behavior—increasingly important information as oil activity spikes and sea ice shrinks.

Den Acoustics

PBI scientists recently completed a pioneering study of the polar bear's hearing range.

Now that we know how sensitive polar bear hearing is, Project Leader Megan Owen of the San Diego Zoo's Institute for Conservation Research, and a member of our Advisory Council, is testing how noise from vehicles and machinery travels through the snow where female bears dig their maternity dens.

To do this, Owen and her team created artificial dens on the North Slope of Alaska and equipped them with recording devices. They're now documenting which industrial sounds penetrate the snow dens and from what distances.

The knowledge gained will help authorities set guidelines for industries working in sensitive areas where female polar bears den with their cubs.

FLIR Den-finding Techniques

Scientists use Forward-Looking InfraRed (FLIR) technology to detect polar bear dens under the snow. PBI researchers are refining techniques to improve the accuracy of this amazing tool, which detects a polar bear's body heat as scientists fly overhead.

Under the direction of Dr. Tom Smith, our researchers constructed a series of artificial dens on Alaska's North Slope. They equipped them with heaters that emit roughly the same amount of heat as a denning polar bear family. Scientists then fly overhead with FLIRs to discover which methods work best for finding the dens.

It's important to locate and map polar bear den sites each fall so that industries working in the area can avoid disturbing mothers and their cubs.

PBI wishes to thank Bering Time, the Columbus Zoo and Aquarium, Utah’s Hogle Zoo, and BP Alaska for supporting the Maternal Den Studies.