Blood Tests Prove Arctic Polar Bears Going Hungry

Western Arctic polar bears are finding it increasingly challenging to find food during the critical spring period, a recently completed study suggests.

The study was done by University of Alberta and Environment Canada scientists. Seth Cherry and Andrew Derocher concluded these polar bears are going hungry, by comparing blood samples taken from polar bears in 1985-86 to samples taken 20 years later, when Arctic sea ice was at or near record lows.

The scientists measured the ratio of urea to creatinine— waste materials found in bears that are byproducts of metabolism—to determine whether an animal is fasting.

Mature males often fast in the spring season, so it is of no surprise to find some polar bears were not eating for considerable periods of time.

The new blood samples, however, showed a sharp increase in the number of bears that were fasting, and of the length of time of each fast.

"The large-scale changes to Arctic marine ecosystems that have occurred since the beginning of this study appear to be affecting the hunting success of polar bears in the Beaufort Sea," Cherry said.

"The nutritional stress we are currently observing could be a precursor to future population declines if sea-ice conditions remain the same or worsen."

Published: January 14, 2009