The dramatic pursuit formed part of a pioneering research mission in Norway's Svalbard archipelago, where scientists, for the first time, took fat tissue biopsies from polar bears to study the impact of pollutants on their health.

The expedition came at a time when the Arctic region was warming at four times the global average, putting mounting pressure on the iconic predators as their sea ice habitat shrank.

"The idea is to show as accurately as possible how the bears live in the wild — but in a lab," Belgian toxicologist Laura Pirard said.

"To do this, we take their (fatty) tissue… and expose it to the stresses they face, in other words pollutants and stress hormones," said Pirard, who developed the method.