1/22/2016 2:44:30 AM
Polar Bear Body Condition Index
Can you tell how healthy a polar bear is just by looking at it? How do you describe how fat or skinny a bear is?
Polar Bears International, in collaboration with partners, has developed a Body Condition Index card to help answer those questions.
Bears need stored fat to survive and reproduce, and fat is indicative of overall health and condition. It's hard to quantify how much fat a bear has in the field without handling the animal and having the right technology at hand.
That's where the Body Condition Index card comes into play. It provides a standardized way to rate bears in the field through visual observation, and in some cases palpation, or touch (if they are safely sedated). Over time, records of body condition across years and regions will help us monitor individual condition, as well as how broader populations may be affected by large-scale environmental change, including loss of sea ice due to climate change.
The original project was conceived by Polar Bears International (PBI) volunteer Diana Weinhardt and completed in conjunction with Dr. Steven Amstrup and Geoff York, now with PBI, when they worked for the U.S. Geological Survey in 2007. After hearing suggestions on how to improve the card over the ensuing years, York led an effort to revise it in 2015.
The Body Condition Index is based on veterinary body condition cards common for livestock and domestic pets and informed by a paper on body condition by Ian Stirling, Gregory W. Thiemann, and Evan Richardson.
In the abstract to the paper, Quantitative Support for a Subjective Fatness Index for Immobilized Polar Bears (Journal Of Wildlife Management, January 2008), the researchers wrote, "Our data demonstrate that the FI (fatness index) rating accurately reflects overall body condition, regardless of polar bear age, sex, or nutritional phase. We suggest that continued field use of the FI rating could provide valuable information on ecological effects of large-scale environmental change on polar bear populations."
York worked with wildlife illustrator Emily Damstra and a team of volunteer advisors from the IUCN Polar Bear Specialist Group in revising the card. They used photographs of wild bears from several regions and in various body conditions to refine the illustrations.
The initial audience was research scientists in the field—the index helped ensure that everyone was using the same criteria to assess polar bears across their range. That audience has grown and now the card is used by hunters, polar bear deterrence staff, Arctic workers, Arctic visitors, and is available for use by Arctic residents.
PBI will use the card in our Body Condition Project—a program to gather information on the body condition of polar bears during the Western Hudson Bay migration each fall.
To the back of the card, PBI added a bear safety primer. "The bear-safety aspect targets visitors to polar bear country as part of our ongoing efforts to reduce bear human conflict," York said. "We have also made the revised BCI card available to government partners for use in their own outreach efforts and under their own logos."
In areas where polar bears are still legally harvested by Arctic peoples, many governments collaborate with hunters to obtain biological samples and other information, such as body condition, from harvested animals. The BCI card is also useful for people working or recreating in polar bear country in an effort to provide more significant information to bear encounter reports.
Body Condition Index card collaborators and advisors
- Geoff York, Polar Bears International
- Steven Amstrup, Polar Bears International
- Andrew Derocher, University of Alberta
- Martyn Obbard, Ontario Ministry of Natural Resources and Forestry
- Todd Atwood, U.S. Geological Survey
- Eric Regehr, U.S. Fish and Wildlife Service
- Kristin Laidre, University of Washington
- Ian Stirling, University of Alberta
- Gregory W. Thiemann, York University
- Evan Richardson, Environment Canada