How do polar bears get so fat – gorging on blubbery seals – without clogging their arteries and becoming a big furry heart attack waiting to happen?
The answer: ‘bear necessities’, genetically speaking.
Scientists conducting genetic analyses of polar bears and their closest cousin the brown bear found that, since diverging from brown bears less than 500,000 years ago to become a new species, polar bears have undergone remarkable genetic changes to permit the high-fat diet they need in the frigid Arctic conditions they call home.
Multiple genes related to cardiovascular function and fatty acid metabolism have changed radically through mutations to permit a high-fat menu without high risk of heart disease, the researchers said, in the study that was published on May 8 in the journal Cell.
“For polar bears, being very fat is no problem,” said Eline Lorenzen, a molecular ecologist at the University of California, Berkeley.