Southern Hudson Bay polar bears become thinner as sea ice disappears

Using a body condition index (BCI) that considered mass and length, researchers found that polar bears in the southern Hudson Bay region experienced declining body condition due to sea ice loss. A positive BCI indicates bears are in better condition than a typical bear in the 1980s, and a negative BCI indicates bears are in worse condition than a typical bear in the 1980s.
Adult male bears
1980s2000s-1012 BCIDecliningbody conditionindexBelow averagebody conditionBelow averagebody condition
Mother bears
1980s2000s-1012 BCI
Females without cubs
1980s2000s-1012 BCI
Bears (aged 2–4)
1980s2000s-1012 BCI
Cubs (aged 1)
1980s2000s-1012 BCI
Cubs (aged <1)
1980s2000s-1012 BCI
Source: Obbard et al. 2016. Trends in body condition in polar bears (Ursus maritimus) from the Southern Hudson Bay subpopulation in relation to changes in sea ice. Arctic Science.
Credit: Kati Perry, Andrew Milligan and Camille Fassett
The Associated Press