Generally speaking, Polar Bears in the Arctic can choose between two strategies for summer, with both their advantages and disadvantages. Naturally one would expect the bears to be out on the ice. This is one of their possible strategies. This is where their preferred food is, seals, and where they have developed and learned most hunting strategies.
Trying to stay on the ice in summer assures the bears will have enough food available, but it also means they have to travel considerable distances and spent a lot of energy in trying to find them. Their habitat is always changing, and local knowledge doesn’t exist. On average only one in twenty hunting attempts are successful for most bears. But on average these bears will be well fed. So are these bears I found near Kapp Mohn. Not on the sea ice, but along the glacier front of one of the biggest icecaps in the world: the Austfonna. Enough icebergs to keep on hunting throughout summer. Looking at these bears, it was apparent they were doing well. The cub (1.5 years old and probably male) was nearly as big as the mother and still had over half a year to go before he had to feed for himself.
The alternative is to stay in the fjords. Here there is far less food available, only the occasional seal in front of a glacier or a dead whale that washes ashore. However, these bears do not need as much energy as the others do. They know their fjords very well, know where to go to try and find food and do not spend as much energy. Most of their time they spend resting or sleeping to minimise their energy loss. However, with little food available, they have to live on their fat reserves which they have to get in winter when the fjords are frozen. In summer, they often look skinny as this is their lean time. So does this bear. Most likely this bear has lived all her life in the area I saw her in, and she knows where to go. This year she has a cub, only one, her other has most likely died already. And even then, she looks skinny and most of the summer lay still ahead of her. Her cub is the same age as the one in the previous photo, 1.5 years old. Now, this might be a female (hard to say for young animals), but the difference in size between the cubs in both photos is enormous. Apart from the possible sex difference, having less food is another likely cause of this. Not the best start in life.