Driven by demand for its pure white fur, the Arctic fox was only saved from extinction by a hunting ban in 1928. But almost a century later, the species is still clinging on.

One reason for its slow recovery is the age-old boom and bust cycle of its primary prey, the Scandinavian lemming. While Arctic foxes produce big litters when lemmings are abundant, they give birth to very few pups or none at all when lemmings are scarce. A lack of lemmings also makes it harder for foxes to survive the winter.

But Arctic foxes are now facing new dangers. They live in the open tundra beyond the treeline. Temperatures there have risen by one degree Celsius over the last hundred years, pushing the treeline deeper into the fox’s territory. And with the trees has come a new competitor - the Arctic fox’s much larger cousin, the red fox. Not only does the newcomer colonise their dens, it can also kill the smaller Arctic foxes.

However, Arctic fox numbers have risen from 30 to more than 200 since 1980, thanks to the tireless work of nature wardens and scientists, and WWF’s successful feeding programme. This initiative has helped many foxes survive the hungriest times of the year when metre-deep snow covers the tundra.

This summer saw a record number of births, with pups being born in areas where foxes have not been seen for years. But we urgently need your support to give all these pups a fighting chance of living until spring.

Arctic foxes swap their thick white fur for a brown coat after winter. It is one of the many astonishing facts about this remarkable animal. And by expanding our feeding programme, we are hopeful that most of this year’s pups will survive to shed their white coats in spring.

WWF’s efforts to save the Arctic fox in Sweden are based on the latest science. We have co-financed projects run by Stockholm University, which have helped to fill in many of the gaps in our knowledge of the fox’s life cycle. This research has enabled us to identify the key threats at different times of the year and design the most effective ways to deal with them.

We found that most pups starve to death during winter. So WWF began providing supplementary food at dens to help the pups survive. But we also decided to provide food all year round at some feeding stations to ensure that some Arctic fox pairs breed every year, even when lemmings are in short supply.

But that is not all. We also co-financed a collaborative project involving Norway and Sweden, which saw captive-bred foxes released into the wild in Norway. Some of these foxes later moved to Sweden and began to breed. Our efforts are really paying off.