Scientists have found that polar bears face the threat of starvation as the Arctic sea ice melts due to global warming. The Arctic bears have struggled to adapt their diets to living on land, which could prove detrimental to their survival. Bear’s diet consists of ringed seals that they catch on ice floats offshore, but while on shore, they’re limited to berries, grass and bird’s eggs. This resulted in the animals losing weight rapidly, as they now lack the high concentration of fat found in ringed seals. A study published in 'Nature Communications' found that warmer, ice-free periods in the Arctic have increased by 3 weeks between 1979 & 2015. Researchers tracked 20 polar bears over 3 years using GPS video camera collars, as well as taking blood samples & doing regular weight checks. 19 of the 20 bears lost body mass, some up to 11%, which works out, on average, as losing 1kg per day. "Regardless of which strategy they used, there was no real benefit as far as being able to prolong the period they could survive on land. One sub-adult female found a dead beluga whale; she took a couple of bites but mostly used it as a buoy to rest on," Dr Anthony Pagano of the US Geological Survey told BBC News. He added that “it suggests to us that these bears can’t eat and swim at the same time."