Next to the thin polar bear and her cub, the sleeping walruses look enormous.
They were spotted by Travis Wilkinson in July of 2015 just after midnight. Because they were in Svalbard, a Norwegian archipelago in the Arctic north, it was still light enough for Wilkinson to capture the bears on video.
He and his family were in the middle of a sailing trip. In the days prior, they had been farther north, but as they sailed south, the ice began to loosen and eventually transitioned into water. Wilkson says the route, sometimes impassable, was particularly free of ice that summer.
In his video, you can see the mother bear approach the sleeping walrus, cub following at her heels. Warily, she inspects each one before finally approaching and pawing at one of the walruses.
The move snaps the walrus to attention, scaring the bear off.
It's likely the bear was checking to see if the walrus was weak enough to become a potential meal, says Jon Aars, a scientist at the Norwegian Polar Institute in Norway.
MOTHER POLAR BEAR, DESPERATE FOR FOOD, TESTS WALRUS
In his video footage, the adult female can be seen wearing a collar. Aars says he's the one who put it there.
He and a team of researchers have been studying how polar bear populations are faring in the Barents Sea. In a study published last October in the journal Polar Research, he and his research team found polar bears had "experienced a rapid loss of sea-ice habitat in the Barents Sea" at least partially attributable to climate change, though there's not yet evidence that this will lead to a decline in population.
Polar bears depend on sea ice to hunt. They can become particularly vulnerable to starvation during summer months while they wait for thawed ice to return.
A study published just last week in the journal Science looked at polar bears on a global scale and found that, overall, global warming puts the species at risk of starvation.
It's nearly impossible to say what caused these bears to become so skinny without a physical analysis.
But unquestionably, said Aars, they're desperate for food.
In an email with National Geographic, he visually assessed the bears and noted that it looks as if the adult female bear is not healthy enough to produce milk.
"My guess is [the cub] would very likely die soon if the mother did not find any food," he added.
Adult male polar bears will sometimes hunt walruses, but the smaller females, especially when malnourished, lack the strength necessary to take down the much larger predator.
By cautiously sniffing the walruses, the adult polar bear is checking to see whether it can easily be killed (or ideally for the bear, whether it is already dead).
"Finding it is a healthy walrus, the answer is no" for the bear, said Aars.
Additional Reporting by James Burch